it might be déjà vu as Democrats happily compare several new conservative Senate candidates to Christine O’Donnell, the tea party darling who infamously cost Republicans what should have been a surefire seat.

The latest is Tuesday’s Missouri primary victor, the six-term conservative Rep. Todd Akin, who defeated two more moderate Republicans better positioned to unseat the highly vulnerable Sen. Claire McCaskill (D-MO).

Akin’s past includes praising a militia group linked to anti-abortion extremism in the 1990s and voting against creating a sex-offender registry in 2005. Back in 1991, as a state legislator, Akin voted for an anti-marital-rape law, but only after questioning whether it might be misused “in a real messy divorce as a tool and a legal weapon to beat up on the husband,” according to a May 1 article that year in the St. Louis Post-Dispatch (via LexisNexis).

He still leads McCaskill narrowly, but Democrats believe that will change as voters get to know him. As a congressman, Akin has a storied history as one of few Republicans to vote against popular programs such as child nutrition and autism services.

In May, Indiana Republicans ousted 36-year Sen. Dick Lugar in favor of state Treasurer Richard Mourdock, who famously says his idea of compromise is Democrats accepting the Republican viewpoint. He’s polling dead even with Rep. Joe Donnelly (D-IN), the Democratic nominee. Lugar, by contrast, was widely seen as untouchable in a general election...

Next Tuesday, in a close three-way Wisconsin primary, Democrats are hoping tea party-backed Mark Neumann pulls out a victory, seeing him as the candidate they’re best positioned to defeat. The Club for Growth, which helped unseat Lugar, is backing Neumann.