DES MOINES, Iowa -- Wisconsin Gov. Scott Walker and his supporters sought to overpower a boisterous group of protesters seeking to interrupt his soapbox speech at the Iowa State Fair on Monday.
"This is a great test with the protesters because, you think you want someone tough, there's a lot of people that talk tough," Walker said. "I'm the only one who stood up to 100,000 protesters, stood up to the union bosses."
Thousands of protesters descended on the state capitol in Madison, Wisconsin in 2011 during Walker's high-profile battle with labor unions. After his speech, Walker told reporters that he thinks the protesters here came from Washington, D.C. or were "directed by Washington-based groups."
The Des Moines Register's Soapbox is a rite of passage for presidential candidates competing in the Iowa caucuses. Protesters are not uncommon once candidates take the stage in front of often unpredictable crowds.
"He said he's not intimidated by anyone, obviously he's not," one of the protesters said after the speech. "That's one reason why we weren't going to haggle him because I think that fuels the fire."
A CNN/ORC poll of Republican caucus-goers last week showed that Walker has slipped to third place in the key early nominating state after once holding the top spot. The survey showed him at just nine percent support, compared to 14 percent for former neurosurgeon Ben Carson and 22 percent for Donald Trump.
Walker told NBC News' Kelly O'Donnell that Trump's rise is "a reflection of people that are extremely frustrated with Washington" and said it is too early in the race to be worried about stalling poll numbers.
The Wisconsin governor also took on his own party, telling the crowd "I'm frustrated with the Republican leadership in Washington as well. You see, they told us during the last election that if we just elected a Republican Senate, the leadership out there would put a bill to repeal Obamacare on the desk of the president."
"It's August. We're still waiting for that measure."
Walker told Iowans that he is the only Republican in the crowded GOP field that has actually "fought and won," citing his three statewide elections in four years in Wisconsin.
"There's a lot of good Republicans in this race, a lot of them talk a big talk about taking on Washington…Given the chance to be president of the United States, I won't just talk about fighting. I'll fight. I'll challenge the status quo in Washington and I will win that fight," Walker said after the speech.
Walker then spent several hours with a beer and pork chop in hand, shaking hands and taking pictures with people on the fairground. He was joined by his wife Tonette, son Matt, and Iowa's Lt. Gov. Kim Reynolds who helped him on the grill at the Iowa Pork Producers tent.
After the fair Walker will make two more stops in Iowa, a part of his effort to complete a "full Grassley" and visit all 99 counties in the state, a reference to Iowa Sen. Chuck Grassley.
Tuesday he will be in Minneapolis to lay out what he said will be a "very specific plan" to repeal Obamacare immediately.
-- NBC's Andrew Rafferty contributed to this report.