ATLANTA (AP) — For all the wrangling between the tea party and establishment conservatives in this midterm election year, key players from both sides are closing ranks behind one candidate in Georgia's Republican Senate primary runoff.

Tea party favorite Karen Handel will announce Wednesday that she's backing U.S. Rep. Jack Kingston over businessman David Perdue in a July 22 runoff, Kingston's campaign confirmed to The Associated Press.

It comes the same day that the U.S. Chamber of Commerce, an establishment titan that spent almost $1 million supporting Kingston in the initial primary campaign, announced another statewide ad buy for Kingston. The spot features Georgia Bulldogs football hero and Heisman Trophy winner Herschel Walker.

Handel, a former Georgia secretary of state, finished third in a May 20 primary for one of the nation's most closely watched Senate races. The Republican nominee will face Democrat Michelle Nunn in a Nov. 4 general election that will help determine which party controls the Senate for the final two years of President Barack Obama's administration.

The GOP needs six more senators to claim a majority and cannot afford to lose the seat opened by the retirement of Saxby Chambliss.

Handel was sharply critical of Kingston, an 11-term congressman, and Perdue, a former corporate CEO, leading up to the first round of voting.

"It's the career politicians and the out-of-touch elitists who have gotten us into this mess," she said at one debate.

Her most personal exchanges came with Perdue, who suggested she wasn't qualified for the Senate because she has only a high school diploma. But she still lambasted GOP incumbents like Kingston. "Republicans had control of the House, Senate and White House" during part of the second Bush administration, she said while campaigning. "What did we do? Nothing. We did nothing."

In a statement released Wednesday, Handel praised Kingston as "a man who is fiercely dedicated to the conservative principles that are the foundation of the Republican Party." And she urged voters to support "the man who has spent the better part of his life serving Georgia."

Her decision is the latest in a string of developments that allow Kingston to pitch himself as a unifying conservative, but it also highlights the narrowing gap between the archconservative activists and the established powers they have sharply criticized.

Kingston's endorsement list puts the chamber — which has promised to spend lavishly to quash the tea party influence in the 2014 midterms — alongside several notable conservatives who've switched their allegiances from Handel. They include national Tea Party Express leader Julianne Thompson and RedState.com editor Erick Erickson, both Georgia residents. Kingston already had an endorsement from Fox News personality Sean Hannity.

In the Senate, that could force Kingston into a tight spot on certain issues. The chamber supported a Democratic-led overhaul of immigration law and a bipartisan deal to reopen government last fall and raise the nation's borrowing limit. In the House, Kingston sided with tea party interests in opposing both efforts.

Perdue has the endorsement of Georgia radio host and failed presidential candidate Herman Cain. But Perdue incensed some conservatives the week before the May 20 primary when he told a Georgia newspaper that it would take both spending cuts and revenue increases to balance the federal budget.

He later noted that he's signed a pledge to oppose all tax increases. He insists that he meant to push policies that would yield economic growth and, thus, more tax revenue. But Handel, Kingston and others said his remarks were code language for a tax increase.