DAVENPORT, Iowa – If you were looking for a sign of how much outside money is shaping politics these days, Saturday night’s Senate debate in Iowa provided a doozy.

In an hour-long debate here, Rep. Bruce Braley (D) and state Sen. Joni Ernst (R) spent a full 11 minutes rebutting attacks aired on television from various super PACs and other outside groups. Braley was asked if he and former New York mayor Michael Bloomberg (I) were “buddies.” Ernst was asked if she had signed a pledge to the Koch brothers, the billionaire conservative industrialists.

By the end of the spirited back-and-forth, the two candidates reached some apparent agreement. Braley called on Ernst to tell the outside groups to take down their ads “and let Iowans decide this election.”

“I think it’s the worst thing that happened to our democracy,” Braley said, drawing applause from the audience of roughly 750.

Ernst’s response was, “Yes.” She said she believes some reforms could be made and noted that she was being outspent on the television airwaves by pro-Braley groups, although she did not explicitly answer Braley’s call that outside groups take down their ads.

In Iowa, more than $34 million has been spent by outside groups in the race to fill the seat becoming vacant with the retirement of Sen. Tom Harkin (D), according to the Center for Responsive Politics. Only the North Carolina and Colorado Senate races have seen more outside money, according to the group’s tally.

At Saturday’s debate in Davenport, the second of three planned debates between Braley and Ernst, the moderators asked Braley whether he was “buddies” with Bloomberg, as suggested in an ad by the National Rifle Association.

“I’ve never met Michael Bloomberg,” Braley said, drawing laughter from the audience. “I have no idea what these ads are based upon other than a fear that I’m going to bring balanced common sense to trying to come up with reasonable solutions to reducing gun violence.”

Republicans quickly responded by circulating a 2010 news release from Braley’s office announcing that the congressman had spoken in New York at the launch event of No Labels, joining Bloomberg and other politicians.

This does not necessarily mean that Braley and Bloomberg met.

Moderators asked Ernst about ads linking her to the Koch brothers and asked whether she had signed a pledge with them.

“No,” Ernst said, laughing. “I have not signed a pledge with the Koch brothers.”

She said there was “so much misinformation” on television and singled out Senate Majority PAC, run by longtime advisers to Senate Majority Leader Harry Reid (D-Nev.), and California venture capitalist Tom Steyer, whom she labeled an “extreme environmentalist.”

Braley countered that Ernst attended two secret donor meetings in California hosted by the Koch brothers, where she credited them with helping launch her Senate campaign.

Ernst’s retort: “This is from someone that’s being supported by [a] California billionaire extreme environmentalist who’s opposing the Keystone Pipeline.”

Overall, the debate touched on many of the issues that have been driving the Iowa contest, which is one of the country’s most contentious contests and looked at by party leaders in Washington as a bellwether in determining whether Republicans or Democrats control the Senate.

A Des Moines Register-Bloomberg News poll released Saturday night showed the race a virtual tie, with Ernst leading Braley 47 percent to 46 percent, within the poll’s margin of error.

Braley, a proud populist, and Ernst, a proud conservative, explained their stark philosophical differences on issues ranging from the environment to healthcare to Social Security to gun control. Ernst summed up the differences by saying in her closing argument, “I disagree almost completely with Congressman Braley and President Obama on just about everything.”

As they have throughout the Iowa campaign, differences in personality and character rose to the surface in Saturday’s debate. Braley repeatedly said, “Sound bites have consequences,” a reference to Ernst’s record of making controversial statements during the Republican primary campaign earlier this year.

“Senator Ernst is fond of saying things that sound good, but when you look at what they mean to Iowans, they don’t make Iowans better off,” Braley said.

Ernst raised Braley’s comments at a closed-door fundraiser in Texas in which he questioned the credentials of popular Sen. Charles E. Grassley (R-Iowa) to chair the senate Judiciary Committee because he was a farmer who had not gone to law school.

“Behind closed doors at a fundraiser in Texas, you poked fun at Senator Grassley for being just a farmer,” Ernst said.

The audience responded with applause and knowing laughter. Braley’s remarks are familiar to many Iowa voters, of course, because pro-Ernst super PACs have featured the clip prominently in their TV ads.