After forty years of struggle no formula had been found which would satisfy the aspirations for local self-government and at the same time secure the external union so essential to the welfare of the whole country. The questions between the provinces and Buenos Aires, and between the different cities which were rivals in the race for national leadership, seemed to a superficial glance to be as far as ever from solution. There had, however, been a shifting of the material balance of power which was soon to change the situation. The provinces had suffered most severely from the long civil wars. Corrientes was well-nigh a desert, in Santa FÉ the Indians roamed up to the gates of the capital town, and the Andean provinces were isolated and poor. The long peace under Rosas's rule had increased the wealth and population of Buenos Aires. The city lost hundreds of enthusiastic young liberals, but it gained thousands who fled from the disorders of the interior. Its population had doubled since his accession. Thirty thousand English, Irish, and Scotch had crowded in to engage in sheep-raising, and the rural population of Buenos Aires province was nearly two hundred thousand. City and country together had doubled, while the rest of the confederation had only increased one-half. The capital province now contained twenty-seven per cent. of the total population, and the disproportion in wealth and percentage of foreigners was far greater. The number of sheep increased from two and a half million in 1830 to five times that number, and by 1850 there were eight million cattle and three million horses in the single province.

All over the country rational ideas about government had made progress. The people were thoroughly sickened of military rule. Civilisation, education, and general intelligence were spreading their beneficent influences; industry, commerce, and the pursuit of wealth were absorbing more of the national energies.

Urquiza, greatest of the caudillos, saw that without peace and union Entre Rios could not be insured prosperity. He had no sooner entered Buenos Aires than he took measures looking to the framing and adoption of a federal constitution. After his victory he was named provisional director of the confederation, but he showed no wish to play the rÔle of a Rosas. All the governors met and agreed to the calling of a Constituent Congress, in which each province was to have an equal vote. As a further precaution against the predominance of Buenos Aires the session was to be held in Santa FÉ. The provinces were anxious to form a strong federation and the only opposition came from Buenos Aires. Her statesmen did not realise that she was bound to be the centre of the system and that the pull of her superior mass would, before many years, be sufficient to control the aberrations of the satellites. Though the governor of Buenos Aires had agreed on behalf of his province, and though Urquiza's military power was overwhelming, the legislature of that province refused its assent. It was clear that Buenos Aires and the other provinces would not be able to agree upon a basis of union. The ambitious cities of the interior each aspired to take the place of Buenos Aires as the capital, and to this humiliation the latter city would never submit unless after another civil war.

Urquiza determined not to use force, and retired to his ranch. As soon as he was out of sight, the city rose in arms against his nominees. The broad-minded Entre Rios chieftain sent back word that he had won the battle of Caseros for the sole purpose of giving Buenos Aires her liberty and that he would not now intervene to prevent her making the use of it she chose. He even disbanded his troops. However, when the Buenos Aireans marched an army to the attack of Santa FÉ where the Constituent Congress, attended by delegates from all the other provinces, was holding its sessions, he again took the field. A counter-revolution broke out in the rural districts of the Buenos Aires province against the faction dominant in the city. Urquiza joined his forces to theirs and besieged the town. A land siege was useless without a blockade on the water side, and Urquiza tried to establish one. He was unsuccessful because the commanders of his ships treacherously betrayed him, surrendering to the city party for a heavy bribe. He raised the siege and retired to the northern provinces.

Buenos Aires virtually declared her independence of the other provinces by this action, but the latter took no further steps to force her into their union. Urquiza and his followers had, however, accomplished more toward uniting the Argentine into a firmly knit nation than had been done in the previous forty years. The opposition of Buenos Aires helped convince the other provinces of the necessity of a union. With the mouth of the river in the hands of a hostile state more powerful than any one of them separately, the position of Entre Rios, Santa FÉ, or any one of the others, would have been critical. Only by uniting could they hope to maintain themselves and avoid absorption in detail. Intelligent Argentines had long been convinced of the desirability of a firm and enduring union, and the present danger crystallised that conviction in men's minds. Back of all this was Urquiza's influence. At last a military chief had come to the possession of supreme power who was willing to aid his country in establishing a stable and free government, and whose purpose was not merely the gratification of his own love of power. Argentine writers are divided in their opinion of Urquiza's real abilities, and many think that ignorance and irresolution, rather than a lofty patriotism, caused his moderation after his victory over Rosas. Intelligent foreigners, however, who saw the Plate for themselves during this period are unanimous in praising his character, his dignified bearing, his liberality, and his capacities. Argentina had passed the stage when a military dictator was her natural chief. The day for constitutional government had arrived; Urquiza was a product of his time, and consciously or unconsciously embodied the changed political sentiments of his countrymen.

On the 1st of May, 1853, the Constituent Congress adopted a constitution substantially copied from that of the United States of North America—and that constitution, with a few amendments, has continued to be the fundamental law of the Argentine Republic. The navigation of the ParanÁ and the Uruguay was declared free to all the world, largely as a reward to Brazil for her assistance against Rosas, although she protested against the extension of that liberty to any nations except those who had territory on the banks. The city of ParanÁ, in the province of Entre Rios and on the eastern shore of the ParanÁ River, was made temporary capital of the Republic. The various provincial capitals had been unable to agree that any one of them should have the honour and profit of being the political metropolis, and the city of Buenos Aires was selected as the permanent capital, to become such as soon as the province of that name should enter the confederation. The delegates had a double purpose in making this selection. Buenos Aires was the natural commercial and political centre, and, all things considered, the most convenient location in the provinces. In the second place, they desired to weaken the great province of Buenos Aires by cutting it in two, and to curb the city's political influence by placing it directly under the control of the federal government.

Urquiza was naturally selected as the first President, and was recognised by foreign nations. Buenos Aires protested, claiming still to be, for international purposes, the Argentine nation. She did not, however, formally declare her independence and seek for recognition as a new power. Buenos Aires, as well as the confederation, looked forward to the time when she would join the latter. Throughout Urquiza's six-year term, the provinces prospered amazingly. His administration of his province had guaranteed the security of property, and now as President he extended the blessings of peace to much of the rest of the confederation. The new bonds sat lightly on the outlying provinces of the Andean regions, but Urquiza did not stretch his constitutional authority to interfere with them, satisfied to let them learn by degrees that the right of local self-government guaranteed by the paper constitution would be respected in practice. The freedom of navigation caused unprecedented prosperity in the river provinces. The towns on the ParanÁ and Uruguay doubled in population during his six-years' service. Corrientes had been continually ravaged by the civil wars as lately as the last few years of Rosas's reign, but the assurance of peace was all that was needed to start the rebuilding of the houses and the restocking of the ranches. The impulse in population, wealth, and commerce then given to the river provinces has never since lost its force. Foreign capital and immigration were invited and the rivers and harbours carefully surveyed. Rosario, in Santa FÉ, was made a port of entry and began a growth that has made it second only to Buenos Aires itself.

In Buenos Aires events were gradually shaping themselves toward reuniting that province with the confederation. A liberal provincial constitution was adopted, and though the ruling bureaucracy preferred the statu quo, fearing that their own fall from power would follow any triumph of the provincials, they were unable to hold the city in check. It was too evident that the real interests of the city, and even her future commercial supremacy, were menaced by a continuance of the separation. In 1859 the situation became so strained that Buenos Aires marched an army to attack the federal government. Urquiza met it near the borders of Santa FÉ and Buenos Aires, and administered a defeat. He advanced to the city and required his vanquished opponents to agree to accept the constitution of 1853, and to consent that Buenos Aires should become a member of the confederation. He yielded, however, to the wishes of many Buenos Aireans and consented in the interests of harmony, that the question of the dismembering of the city from the province and capitalising the former should remain open for future determination. The essential justice in all other respects of the constitution of 1853 had long been admitted even in Buenos Aires and there remained no reason why the latter should not enter the confederation once and for all. On the 21st of October, 1860, General BartolomÉ Mitre, Governor of Buenos Aires, swore to the constitution, saying: "This is the permanent organic law, the real expression of the perpetual union of the members of the Argentine family, so long separated by civil war and bloodshed."

Meanwhile, Urquiza's term had expired. Dr. Derqui, his successor, was suspected of designs against the autonomy of the provincial governments. The assassination of the Governor of San Juan and the succession of a member of an opposite faction, was made the occasion for Federal intervention in the affairs of that province. The government of Buenos Aires protested and it became evident that this untoward event was soon to disturb the peace of the newly formed confederation. The Federal Congress, under Derqui influence, refused to admit the members from Buenos Aires. Mitre marched out at the head of her forces and at the battle of Pavon, September 17, 1861, he overthrew the provincial forces. Buenos Aires remained mistress of the situation. The governments of certain provinces had been imposed on their people by the Derqui administration, or they were obnoxious to the triumphant Buenos Aires party. They were overthrown and Derqui was deposed. Happily for the Argentine, Mitre was a sincere patriot and, though young, was moderate and conciliatory. Made president of the republic as the representative of the victorious Buenos Aireans, he set about the final reorganisation of constitutional government in a spirit of unselfishness and with a foresight and skill that greatly aided to save his country from the sterilising anarchy of civil war.

The accession of Mitre in 1862 marked the end of the period of uncertainty. The government of the Argentine Republic was now finally and definitely established and fixed, after fifty-two years of conflict. The constitution of 1853 was left unamended, except that Buenos Aires became the seat of federal government without being separated from its province or ceasing to be the provincial capital. The free international navigation of the rivers was not interfered with, and Buenos Aires abandoned her pretensions to special commercial privileges. She was thenceforward more and more the centre of gravitation and power for the whole republic, but her influence came from legitimate natural causes and was exercised within constitutional limits. The autonomy of the provinces was not interfered with, and it was no longer possible, even in the remotest districts, for a caudillo to rally at his call the gauchos, always ready for a raid, a campaign, or an invasion.

Though the form of the federal government was fixed and its theoretical supremacy has never since been questioned, its real power at first was feeble. Urquiza was master in the mesopotamian provinces, and in case of need Mitre could count on little military help except from his own province. The only result of the battle of Pavon which was immediately apparent was the shifting of the centre of power from Urquiza's capital to Buenos Aires. Nevertheless, henceforth the tendency was constantly toward strengthening the bonds of union. Urquiza and the other provincial governors showed no disposition to attack the central authority, and in turn the latter was careful to avoid useless aggressions against them. The problem of reconciling provincial rights with the existence of an adequate federal government had at last been solved. The nation passed on to a still more difficult question,—the smooth and satisfactory working of democratic representative institutions in the absence of an effective participation in public affairs on the part of the bulk of the population. Elections have not carried the prestige of being the expression of the majority will. The ruling classes have been anxious enough to obey the popular voice and to govern wisely, but people can only gradually be trained into the habit of expressing their will clearly and indisputably at regular elections. The insignificant disturbances to public order which have occurred since 1862 have been indications of dissatisfaction with the imperfect detail workings of the complicated system of ascertaining the popular wishes, or hasty protests against mistakes on the part of those in power. Never have they endangered the Federal constitution nor diverted the steady course of the nation's progress in the art of self-government.