On December 8, 1829, Rosas was elected Captain-General in the interests of the Federalists, but he had no intention of allowing Federalist principles to stand in the way of his supreme rule. Lopez was despatched against Paz, who had the misfortune to be accidentally taken prisoner. Showing unusual magnanimity, Lopez spared his life. The troops of the Unitarians never recovered from the loss of their brave leader, and being attacked by the ferocious Quiroga and driven to Tucuman, they were in a hopeless position. Quiroga butchered five hundred prisoners in cold blood, and few of the remnants of Paz's army escaped to Bolivia.
Rosas then employed himself in consolidating his power at Buenos Aires, and with this object he repealed several of the Liberal laws of Rivadavia. In this task he was assisted by a clever and crafty man named Anchorena, with whose collaboration he passed a rigorous law of "suspects" directed against the Unitarians. Severe as he was against that party, and detested as he was by the late holders of office in the capital, who resented the dominion of a rustic, he was really, by his masterful measures, advancing the principle against which he posed as the nominal antagonist.[50] At the end of 1832 his term of office came to an end, and he was re-elected. But as his extraordinary powers were not renewed he haughtily refused office, and left Buenos Aires to reduce the Indians of the Pampa, who had taken advantage of the civil discords of Argentina. Again a man of straw was put at the helm. His name was Balcarce.
In the Indian war Rosas was successful, penetrating as far as the Rio Negro and destroying, according to his own computation, twenty thousand of the enemy. It is not necessary to describe the manoeuvres and hesitations which preceded his return to nominal as well as real power. In 1835 he accepted the title of Governor and Captain-General, and henceforth ruled as a military Dictator. Never was there a more ruthless tyrant. The two most prominent soldiers and possible rivals left in Buenos Aires were Quiroga and Lopez. Quiroga had seen the elevation of Rosas with ill-concealed disgust, and the new Dictator resolved to make away with him. Rosas, therefore, commissioned him to go to pacify Salta and Tucuman, and on his way thither caused him and his suite to be assassinated. Shortly afterwards Lopez died, and it is only necessary to say that his physician was handsomely rewarded by Rosas. He established a reign of terror, and formed a club of ruffians called the Massorca, whose business it was to murder his enemies. One Maza attempted a Parliamentary resistance to him, and the crafty Dictator, after the plan had failed, first lulled him into security by vague promises of safety and then sent four men to stab him to death. His death was followed by an extensive proscription; in fact, the history at this period is distinctly Tacitean.