In 1848 with Whigs on the downslide? With James K Polk of Tennessee as President and Southerners like Robert J Walker of Mississippi setting fiscal policy?
http://millercenter.org/president/polk/essays/cabinet/233

1846-1848 Trade and tariff revenues were so buoyant that the Polk administration did not have to raise taxes to pay for the Mexican War. Existing rates funded more than 60 percent of the $100 million of wartime costs, while borrowing covered the rest. After the war, the persistent robustness of Customs duties enabled the federal government to pay off nearly all its Mexican War debts by the time of the Civil War. Demoralized by the popularity of the Polk administration’s economic programs, congressional Whigs lost their enthusiasm for campaigning on the American System.