CHICAGO (AP) — A former Chicago-area sheriff emerged from a crowded Republican field Tuesday in the Illinois primary, advancing to mount a long-shot challenge against Democratic U.S. Sen. Dick Durbin.

Mark Curran, who had perhaps the most name recognition of all the candidates, said he ran because he believes the political climate has changed and Durbin is vulnerable.

“He has neglected Illinois and nobody has been able to land a punch,” Curran told The Associated Press. “But having been a career prosecutor and the longest-serving sheriff in Lake County, I know how to throw a punch. I’m credible.”

Durbin, the No. 2 Democrat in the Senate, was first elected in 1996 and has handily won each election since then. He also has $4.5 million cash on hand. All the other Republican candidates combined made up only a fraction of that.

Curran, who led in endorsements, was previously a Democrat but switched parties in 2008.

Two other candidates had also switched parties. Perennial candidate Robert Marshall, a Burr Ridge doctor, previously ran as a Democrat, including for governor.

Peggy Hubbard of Belleville, a former police officer, said she became a Republican after the fatal shooting of Michael Brown in Ferguson, Missouri, in part because of how former President Barack Obama handled it.

Hubbard sparked a police investigation when she claimed during a candidate forum at a school that she brought a gun to illustrate safety lapses. Hubbard later said she misspoke.

The two other Republicans were Tom Tarter, a retired cancer surgeon from Springfield, and Casey Chlebek, a Glenview man originally from Poland who works in real estate.

Durbin, who was unopposed in the primary, issued a statement saying he was honored to continue the campaign and work to "restore this nation to the honorable, decent country that we know and love.”

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