Wisconsin Sen. Tammy Baldwin wins re-election to U.S. Senate

Sen. Tammy Baldwin (D-WI) speaks as Sen. Mark Warner (L) (D-VA) and Senate Minority Leader Charles Schumer (R) (D-NY) look during a news conference on Capitol Hill on March 14, 2017 in Washington, DC. (Photo by Justin Sullivan/Getty Images)

Democratic U.S. Sen. Tammy Baldwin has won a second term, defeating Republican challenger Leah Vukmir. 

Baldwin led Leah Vukmir in fundraising and polls throughout the race. 

The Associated Press contributed to this report.