[2] Congress, in 1847, passed another internal improvements bill; he pocket vetoed it and sent Congress a full veto message when it met in December. Similar bills continued to advance in Congress in 1848, though none reached his desk.[231] When he came to the Capitol to sign bills on March 3, 1849, the last day of the congressional session and his final full day in office, he feared that an internal improvements bill would pass Congress, and he brought with him a draft veto message. The bill did not pass, so it was not needed, but feeling the draft had been ably written, he had it preserved among his papers.[2]

The California Gold Rush began in Polk's last days in office.
Authoritative word of the discovery of gold in California did not arrive in Washington until after the 1848 election, by which time Polk was a lame duck. Polk's political adversaries had claimed California was too far away to be useful and was not worth the price paid to Mexico. 