Reagan, a Republican from California, took office following a landslide victory over Democratic incumbent President Jimmy Carter in the 1980 presidential election. The 1980s saw the highest rate of immigration to the United States since the 1910s, and the proportion of the foreign-born population reached its highest level since the 1940s. Reagan did not make immigration a focus of his administration, but he came to support a package of reforms sponsored by Republican Senator Alan Simpson and Democratic Congressman Romano Mazzoli, which he signed into law as the Immigration Reform and Control Act in November 1986.