The poll, from Democratic polling firm Public Policy Polling, gives Rep. Steve King (R) a wide lead on all other potential Republican primary challengers tested — but King still lags every possible Democratic contender in a general election matchup.

According to the survey, in a four-way Republican primary matchup, King receives 41 percent of the vote to 22 percent for Rep. Tom Latham, 10 percent for Lt. Gov. Kim Reynolds, and nine percent for conservative leader Bob Vander Plaats.

With the field narrowed to just King and Latham, King leads his congressional colleague with 50 percent support to Latham's 27 percent.

That 23-percentage-point lead over Latham is largely due to his appeal among "very conservative" voters, who back King with 61 percent support.

Those are typically the types of voters that go to the polls during a primary, and the types of voters that helped nominate a number of GOP senate candidates in 2012 that Republicans lamented were not ready for primetime, after they failed to make it through the general election.

That story could play out again in Iowa, as although King leads all potential Republican challengers substantially, he lags all Democrats.

Rep. Bruce BraleyBruce Lowell BraleyOPINION | Tax reform, not Trump-McConnell feuds, will make 2018 a win for GOP Ten years later, House Dems reunite and look forward Trump: Ernst wanted 'more seasoning' before entertaining VP offer MORE (D) leads him with 49 percent support to King's 38 percent, while Secretary of Agriculture Tom VilsackThomas James VilsackUSDA: Farm-to-school programs help schools serve healthier meals OVERNIGHT MONEY: House poised to pass debt-ceiling bill MORE has a similar 10-percentage-point lead on King. PPP also tested former Gov. Chet Culver and Rep. Dave Loebsack (D), both of whom lead King by seven percentage points.

Latham fares better against the possible Democratic contenders, lagging Braley and Vilsack by only four percentage points, and leading Culver by four percentage points and Loebsack by three percentage points.

The fear that a candidate who might be weaker against Democrats will make it through a primary prompted the recent creation of a super-PAC, the Conservative Victory Project, with the specific aim of engaging in primary races to help nominate the most conservative candidates who are also electable.

The CVP was launched by Karl Rove and will be backed by many of the same donors that contribute to his super-PAC, American Crossroads, which played heavily in Senate races but largely stayed out of primaries.

But its creation, and its potential implications, has riled conservative grassroots activists, who charge that establishment meddling into primaries ultimately supports weaker candidates, rather than helping to weed them out.

Some, including Tea Party Express leader Amy Kremer, have warned that the new group could spark a backlash and cause the grassroots to break off from the establishment-backed candidate and support an alternative candidate, further splitting the GOP vote in a general election.

It's still unclear where or how that might happen, but American Crossroads President Stephen Law told the New York Times that the group may see its first opportunity in Iowa.

“We’re concerned about Steve King’s Todd Akin problem,” Law said. “This is an example of candidate discipline and how it would play in a general election. All of the things he’s said are going to be hung around his neck.”

The poll was conducted among 846 Iowa voters, as well as 326 "usual Republican primary voters," from Feb. 1-3 and has an overall margin of error of plus or minus 3.4 percentage points, and plus or minus 5.4 percentage points for the Republican primary results.