Sen. Tom Coburn (R-Okla.) on Wednesday endorsed former Sen. George LeMieux’s uphill battle to win his old job back.

“I served with George and have seen firsthand his commitment to reducing our national debt and stopping Washington’s out-of-control spending,” Coburn said in a statement.

In the Republican primary, LeMieux faces frontrunner Rep. Connie Mack IV, who has the backing of everyone from tea-party-affiliated Sen. Rand Paul (R-Ky.) to presumptive GOP White House nominee Mitt Romney.

The winner of the primary will face two-term Democratic Sen. Bill Nelson, who is in a strong position to win re-election even if President Barack Obama loses Florida.

In the general election, Roll Call rates this race as Leans Democratic.