Rep. Tim Walberg (R-Mich.) backed former state Sen. Nancy Cassis (R) in the 11th district Monday, marking the write-in candidate’s second Congressional endorsement.

Cassis faces an uphill climb to defeat reindeer rancher Kerry Bentivolio, the only Republican on the Aug. 7 primary ballot.

The primary mayhem started earlier this summer, when Rep. Thaddeus McCotter (R-Mich.) abandoned his re-election bid after he failed to collect enough valid signatures to get on the ballot. Only Bentivolio remained on the GOP ballot, but local Republican officials supported Cassis — and now two Members of Congress are joining them.

Rep. Mike Rogers (R-Mich.) previously endorsed Cassis. Freshman Rep. Justin Amash (R-Mich.) supports Bentivolio.

Earlier this month, McCotter resigned from Congress altogether, forcing a special election. Both Republicans are also running the Sept. 5 special primary to serve out the final weeks of McCotter’s term.