The agreement was the only alliance Washington made in the 19th century. It established a strong American role in Central America and was a counterweight to British influence there.[215]
In mid-1848, President Polk authorized his ambassador to Spain, Romulus Mitchell Saunders, to negotiate the purchase of Cuba and offer Spain up to $100 million, a large sum at the time for one territory, equal to $3.13 billion in present-day terms.[217] Cuba was close to the United States and had slavery, so the idea appealed to Southerners but was unwelcome in the North. However, Spain was still making profits in Cuba (notably in sugar, molasses, rum and tobacco), and thus the Spanish government rejected Saunders's overtures.[218] Though Polk was eager to acquire Cuba, he refused to support the filibuster expedition of Narciso López, who sought to invade and take over the island as a prelude to annexation.[219]

Domestic policy[edit]
Fiscal policy[edit]
Polk's official White House portrait, by George Peter Alexander Healy, 1858
In his inaugural address, Polk called upon Congress to re-establish the Independent Treasury System under which government funds were held in the Treasury and not in banks or other financial institutions.