In Wisconsin, Republican voters chose former Wisconsin Gov. Tommy Thompson as the GOP nominee in the race to choose a successor for retiring U.S. Sen. Herb Kohl, a Democrat.
Thompson beat businessman Eric Hovde and Tea Party-backed Mark Neumann, a former state representative, the Milwaukee Journal Sentinel reported. The race has been overshadowed by the unsuccessful effort to recall Gov. Scott Walker and the weekend selection of Rep. Paul Ryan, R-Wis., as presumptive GOP vice presidential nominee by Mitt Romney.
Thompson will face U.S. Rep. Tammy Baldwin in the fall.
Across the state line, in Minnesota, Democratic voters in the 8th Congressional District were deciding on a nominee to take on incumbent freshman Rep. Chip Cravaack in November. Former U.S. Rep. Rick Nolan was leading the Democratic field with about 42 percent of the vote, while former state Sen. Tarryl Clark had 38 percent and former Duluth councilman Jess Anderson had 20 percent, with about 31 percent of precincts reporting, the (Minneapolis) Star-Tribune reported.
In southern Minnesota, where Republicans were choosing a candidate to challenge Rep. Tim Walz in the 1st District, former state Rep. Allen Quist was leading state Sen. Mike Parry, 54 percent to 46 percent, with more than 70 percent of precincts reporting, the newspaper said.
In Florida, Rep. John Mica, a Republican, survived a tough re-election battle that also tested the strength of the Tea Party movement in the Sunshine State, The Hill said.
Republican voters in central Florida's newly remapped 7th Congressional District elected the veteran Mica, chairman of the House Infrastructure and Transportation Committee, over freshman Rep. Sandy Adams, supported by the Tea Party, in what had been considered one of the more volatile intraparty contests.
Florida GOP consultant Alex Patton told The Hill the primary outcome could be indicative of how well Tea Party candidates nationwide will fare nationwide in November.
"If Mica wins, it's a referendum as to the Tea Party's strength in Florida. If Adams wins this one, I think the race is kind of a bellwether for the rest of the nation," Patton said.
However, a Tea Party-backed candidate appeared on the way to unseating veteran GOP Rep. Cliff Stearns. Ted Yoho, a veterinarian, was leading Stearns 34 percent to 33 percent -- a lead of a little more than 80 votes -- with 100 percent of precincts reporting.
The winner will advance to a general election matchup against J.R. Gaillot, a businessman who ran uncontested in the Democratic primary.
In Connecticut, 5th District U.S. Rep. Chris Murphy easily won the Democratic primary and will meet Republican Linda McMahon in the general election in November, with the winner succeeding the retiring Sen. Joe Lieberman, an independent. McMahon -- a former WWE wrestling executive who sank $50 million of her personal funds into a losing U.S. Senate race in 2010 -- beat former U.S. Rep. Christopher Shays to win the GOP nomination.