Image credit: Bruce Smith/AP Photo

Tonight, Mark Sanford will try to leap his second hurdle on the way to an improbable political comeback.

The former South Carolina governor is seeking the House seat he represented in the 1990s - before gaining brief national GOP stardom as a budget-cutting governor who said no to federal money, before his lies about being on the Appalachian Trail, and before his exit amid a sex scandal.

Sanford is competing today in a Republican primary runoff against Curtis Bostic, a Charleston attorney and former member of the Charleston County Council.

In ideology, the two candidates are very similar.

READ MORE: ABC News' full coverage of Mark Sanford's rise and fall.

Sanford has campaigned on fiscal conservatism, touting his record at governor, when he turned down federal stimulus money and accrued momentary cachet as a possible Republican presidential candidate for 2012.

Bostic has been running on the same platform. For his campaign website, Bostic chose the URL "StopSpending.com"-making no mention of his own name.

Sanford is expected to win, despite the lack of any polling in the district that ABC News considers reliable enough to report. His near-universal name recognition is considered Sanford's primary advantage by Republican politicos in the state, and Sanford topped a 16-way primary field on March 19 with 39 percent. Bostic ranked second with 13 percent.

Tonight will signify Sanford's first true test of how voters have received his post-sex-scandal comeback.

In the multi-way primary, he exceeded predictions, but the presence of so many candidates made it difficult to say whether his topping the field marked something to revel in or wring hands over. Tonight, Sanford will face his first head-to-head matchup since the sex scandal that tarnished his tenure as governor.

The winner of today's contest will face Elizabeth Colbert Busch, the sister of Comedy Central personality Stephen Colbert, in a May 7 general election.