WASHINGTON — Editor's note: This article is the fourth in an occasional series about unexpected swing states in the 2004 presidential race. Richard Nixon was the last Republican to capture the Democratic stronghold of Minnesota — back in 1972. But the native state of former Vice Presidents Walter Mondale and Hubert Humphrey — once known as an outpost of the leftist politics of Scandinavia, where many Minnesotans trace their roots — is a swing state in the presidential election.