The Treaty of Guadalupe Hidalgo, in 1848, closed the war. Its chief provisions were:

(1) The Rio Grande was made the boundary between Texas and Mexico.

(2) California and New Mexico were ceded to the United States.

(3) The United States paid Mexico $15,000,000, and assumed $3,500,000 due American citizens.

The slavery question was intensified in American politics.

PRINCIPAL BATTLES
NOTE: The Americans were victorious in every conflict.

Place of BattleDatesCommandersEngaged
AmericanMexicanAmericanMexican
BraciteDec.25,1846DoniphanPonce de Leon5001,200
Buena VistaFeb.23,1847TaylorSanta Anna4,70017,000
Cerro GordoApril18,1847ScottSanta Anna8,50012,000
ChapultepecSept.13,1847ScottSanta Anna7,20025,000
ContrerasAug.20,1847ScottValencia4,0007,000
ChurubuscoAug.20,1847ScottSanta Anna8,00025,000
HuamantlaOct.9,1847LaneSanta Anna5001,000
MexicoSept.14,1847ScottSanta Anna6,000...
Molino del ReySept.8,1847WorthAlverez3,50014,000
MontereySept.24,1846TaylorAmpudia6,60010,000
Palo AltoMay8,1846TaylorArista2,3006,000
Resaca de la PalmaMay9,1846TaylorArista2,0005,000
SacramentoFeb.28,1847DoniphanTrias9004,000
Vera CruzMar.27,1847ScottLandero12,0006,000
The only naval engagements of importance during the war with Mexicowere the bombardment
ofVera Cruz, by Commodore Conner, which lasted four days, and the bombardment of Monterey,
CommodoreSloat, both cities being forced to surrender.

The Democrats, holding that slaves were property, claimed the right to take them into any territory, and asserting the principle of “squatter sovereignty,” claimed the right of the people living in any territory to settle for themselves whether it should be slave or free. The Free Soilers demanded that the soil having been free when a part of Mexico, should be free as a part of the United States. Between these two Clay now stepped in to act as pacificator. Taking up the grievances of each side, he framed and carried through the measure known as the Compromise of 1850, the third great political compromise in our history. The fruit of this was the admission of California as a free state; the passage of a more stringent law for the recovery of fugitive slaves; the abolition of the slave trade in the District of Columbia; and the organization of Utah and New Mexico on the basis of “squatter sovereignty.”

This done, senators and representatives of all parties joined in a manifesto declaring that the issues resting on slavery were dead issues, and that they would neither vote for, nor work for any man who thought otherwise. But thousands did think otherwise. The action of Clay pleased none. Anti-slavery men deserted him in the North; pro-slavery men deserted him in the South; and in 1852 the Whig party carried but four states out of thirty-one and perished. Even its two great leaders, Clay and Webster, were, by that time, in their graves.

Excited by such success, the Democrats, led on by Stephen A. Douglas, now broke through the compromise of 1820 and in 1854 applied “squatter sovereignty” to the organization of the territories of Kansas and Nebraska. Against this violation state legislatures, the people, the pulpit, and the press protested vigorously, for every acre of Kansas and Nebraska lay to the north of 36° 30′ and was solemnly pledged to freedom. But the Democratic leaders would not listen and drove from their ranks another detachment of voters. The effect was soon manifest. The little parties began to unite and when, in 1856, the time came to elect another president, the Republican Party of to-day was fully organized and ready. Once more and for the last time for twenty-eight years the Democrats won.