Indiana Secretary of State Todd Rokita (R) topped a 13-candidate primary field Tuesday in the 4th district, an area so heavily Republican that he is a cinch to win in November and join Congress next year.

Rokita, Indiana’s chief elections officer for the past seven years, won 44 percent of the vote in a race in which his most threatening challenger, state Sen. Brandt Hershman, had 15 percent with more than 60 percent of the vote counted. None of the other 11 Republican candidates topped double digits.

Rokita almost certainly will succeed Rep. Steve Buyer (R), who did not seek a 10th term in a district that includes Lafayette, the west side of Indianapolis and some suburbs of Indiana’s capital city.

Democrats aren’t targeting a district that gave Sen. John McCain (R-Ariz.) 56 percent of the vote in 2008’s presidential election and 69 percent to President George W. Bush in 2004.

The Democratic nominee will again be David Sanders, a Purdue University biology professor who lost badly to Buyer in 2004 and 2006.

Rokita earlier this year weighed a campaign for Senate but chose to run for the House after Buyer announced in late January that he would retire to spend more time with his ailing wife.

Hershman, who also is a longtime Buyer aide, ran with the Congressman’s backing. But Buyer’s late retirement announcement worked to Rokita’s advantage because it was difficult for Hershman to catch up to Rokita in name identification in a three-month campaign. Rokita was elected statewide in 2002 and 2006 and attracted attention for defending Indiana’s voter ID law and promoting changes in the redistricting process.