Updated 3:30 p.m. ET, 5/28/2014
(CNN) - Joni Ernst doesn't have to take sides in the battle between the Republican establishment and the tea party movement.
It seems she's got the backing of both sides.
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The latest example: Wednesday the U.S. Chamber of Commerce announced it's going up with a new ad that supports the GOP state senator from Iowa who's running for the U.S. Senate in the Hawkeye State.
The spot by the pro-business group that usually backs mainstream Republican candidates, comes one day after the Senate Conservatives Action, an arm of the Senate Conservatives Fund, which has a history of backing conservative candidates that launch primary challenges against incumbent Republican senators, went up with its own television commercial in support of Ernst.
"Joni Ernst. Raised on a farm in Montgomery County where she raises her own family. Ernst served our nation's military. A commander in Operation Iraqi Freedom," says the narrator in the Chamber spot.
The Chamber says their ad will run state wide through next Tuesday's primary.
The new commercial by the Chamber comes just two days before Mitt Romney comes to Iowa to campaign with Ernst. The 2012 GOP presidential nominee will team up with the state senator at events Friday in Cedar Rapids and Davenport.
Ernst grabbed national attention earlier this year by touting her hog castrating skills in a campaign commercial. The candidate, a lieutenant colonel in the Iowa National Guard, also made headlines for another provocative TV ad which showed her riding up to a gun range on a motorcycle.
Ernst has the backing of the National Rifle Association, which also normally endorses more mainstream GOP candidates.
Ernst, who was a little-known state senator from one of the most rural parts of Iowa, also enjoys support (but not the official endorsement) from Republican Gov. Terry Branstad and Lt. Gov. Kim Reynolds.
And she was also recently endorsed by the editorial page of the Des Moines Register, the most well read newspaper in the state.
Tea Party Support
But Ernst also has the backing of anti-establishment groups.
"The mother of three, a veteran, a strong conservative, Ernst is running to shake up Washington," says the narrator in the new spot by Senate Conservatives Action.
The commercial includes a clip of Ernst from a rally, where she was joined by former Alaska Gov. Sarah Palin, saying "I stand for the full repeal and replacement of Obamacare,"
The ad ends with the narrator saying that Ernst is "Iowa’s conservative choice for U.S. Senate."
The group says it will spend just over $100,000 to run the spot in the Des Moines market for the week leading up to primary day. Ernst tops the latest polls in the multi-candidate field in the June 3 primary for the GOP Senate nomination. The winner of the primary will face off in the midterm elections against Democratic Rep. Bruce Braley, who faces token opposition in his party's primary.
The winner of November's general election will succeed longtime Democratic Sen. Tom Harkin, who is retiring at the end of the year. Republicans view Iowa as a potential pick-up seat in their drive to win back six Senate seats from the Democrats to retake control of the chamber.
Senate Conservatives Fun, which spent big bucks in support of Kentucky businessman Matt Bevin's unsuccessful primary challenge against Senate Minority Leader Mitch McConnell, is also backing state Sen. Chris McDaniel, who faces off next Tuesday in Mississippi's Republican primary against longtime Sen. Thad Cochran.
Ernst also enjoys the backing of the political wing of Tea Party Express, a leading national tea party group, as well as Sen. Marco Rubio of Florida, who's considering a 2016 GOP presidential bid. Rubio's Reclaim America PAC went up this week with a new TV ad titled "Exceptional" in support of Ernst. The group is spending nearly $200,000 to run the spot statewide on cable TV, digital and radio
So how has Ernst been able to appeal to both sides in the grassroots vs. establishment divide?
"Her legislative record is that of a pragmatic conservative, which certainly gives comfort to mainstream Chamber of Commerce type Republicans. On the other hand, her campaign has adopted a no-nonsense, tough-talking tone more commonly identified with the ideological right," said Iowa GOP strategist and consultant Matt Strawn.
"This, coupled with the failure of other movement conservative candidates in the race to prove electoral viability, has created this unique coalition of support for Ernst," added Strawn, the former chairman of the state Republican party.