Sanford, once a fast-rising conservative favorite, saw his ascendance ended when he admitted to having an affair with an Argentine woman he's now engaged to. He's now running for a House seat he once held, recently vacated when Sen. Tim ScottTimothy (Tim) Eugene ScottSenate GOP urges Trump administration to work closely with Congress on NAFTA Fed nominees vow to rebuff pressure from Trump on interest rates The Hill's 12:30 Report MORE (R-S.C.) moved to the upper chamber. He's facing a crowded GOP in his bid for political resurrection.

Erickson opens by writing that he defended Sanford shortly before his scandal erupted, "buying his story that he was on the Appalachian trail, when he was really chasing Argentinian tail."

Erickson continues on to write that while conservatives rightfully exiled Sanford at the time, "we do a terrible job with forgiveness and rehabilitation."

"Mark Sanford walked out of the Governor's Mansion and out of public life for a while. He comes back as conservatives in Congress are fighting on all fronts, out numbered, depressed, and needing every man capable of manning the ramparts," he writes. "Mark Sanford can man the ramparts. Unlike his opponents, he has a stellar and uncompromising record as a limited government, pro-life, fiscal conservative. I am willing to forgive him. And I'm willing to be graceful.

"We need him. There's no better alternative. He's with us. I endorse him without reservation. I hope the voters of South Carolina will show him grace and put him back in the fight at this desperate hour for fiscal conservatives."