Earlier this month, Thompson won just 34 percent of the GOP primary vote, narrowly defeating two tea-party-backed opponents. He faced a multiple-front attack from conservative groups challenging his connections to President Barack Obama's health care law, his time as a Washington, D.C., lobbyist and even his age. The conservative Club for Growth alone spent nearly $550,000 against him.
Thompson said he thinks Republican voters in Wisconsin have coalesced around his candidacy.
"I would say that 97 percent of the Republicans are supporting me," he said. He called his race "one of the top three Senate races in America," along with Ohio and Virginia.
A Wisconsin delegate who attended the closed-press boat event said the former governor emphasized his continued vigor, despite attacks to the contrary from his much younger primary opponents just weeks ago.
"That he's virile!" exclaimed Trish Schaefer, a 46-year-old resident of Sun Prairie, Wis., when asked what Thompson's message was.
Though he expresses the confidence of a candidate with broad name recognition and a long political career, Thompson has been making moves in the weeks following his primary that belie an acknowledgement that a campaign shakeup was necessary. On Aug. 18, he hired a new campaign manager, Keith Gilkes, who ran Walker's 2010 gubernatorial race. A source familiar with Wisconsin Republican politics indicated that the campaign is currently in transition, with significant staff changes being made.
Throughout the primary, even the most passionate of Thompson's supporters expressed concern that he was not running an aggressive and modern campaign - a flaw that proved fatal in other primaries, such as in Indiana. With the Senate majority potentially hinging on Wisconsin, Thompson needs to ramp up his efforts in the general to secure the open seat that many believe is his to lose.
"What kind of campaign will he run? Is he going to sit back and wait for the votes to roll in or is he going to go out there and pull out the stops?" a Wisconsin Republican operative unaffiliated with Thompson or any of his former primary challengers asked. "It remains to be seen."
Top Republican officials prioritizing winning Wisconsin for the Romney-Ryan ticket likely will favor Thompson, although the presidential race also threatens divert attention and resources away from his bid. National and local operatives of both parties concede that a potential Obama-Thompson voter is much more likely than a Romney-Baldwin one.
Republican National Committee Chairman Reince Priebus, who hails from the Badger State, said this week that he does not see his national responsibilities, or Ryan's, impeding the party's plans to win the Senate race at home. He highlighted the field advantage Republicans have in Wisconsin, gained largely in the historic effort to recall Walker, as one of the party's top weapons in trying to sweep the ballot.
"We're also going to have a massive turnout operation in Wisconsin. There isn't a state in the country that I think - now I've got a lot more intimate knowledge of this - [has] more data on voters than Wisconsin. Tommy is going to benefit from the massive ground operation there and the turnout operation."
Vice President Joe Biden waits to conduct a mock swearing-in ceremony with Sen. Brian Schatz, D-Hawaii, in the Capitol's Old Senate Chamber, December 2, 2014. Schatz was sworn in to serve the remainder of his term since he was appointed to the seat after Sen. Daniel Inouye, D-Hawaii, passed away.