Editor's note: John Avlon is a CNN contributor and senior political columnist for Newsweek and The Daily Beast. He is co-editor of the new book "Deadline Artists: America's Greatest Newspaper Columns."
(CNN) -- Mitt Romney is learning that there are costs to an ugly, extended primary fight marked by a rush to the far right. Independent voters get alienated by the extremism.
Last weekend, Romney was trying to reassure attendees at the Conservative Political Action Conference he was "severely conservative," but that elevation of ideological inflexibility sounds like someone who's hitting the Kool-Aid a little too hard for most independent voters.
This is a problem with polarization -- and it's already showing signs of benefiting President Barack Obama.
After trailing Romney for months among independent voters in a hypothetical matchup, the president is back on top -- 51% to 42% in a new Pew Research Center Poll.
Just four months ago, the numbers were almost reversed, totaling a 19% swing since the primaries began in earnest. This isn't subtle -- it's something close to an outright revolt of the independents in response to the spectacle they've seen in the Republican contests since Iowa -- avalanches of negative ads and an outright pander-fest to various forces on the far right.
A new CNN/ORC International poll finds that 53% of independents have an unfavorable view of Romney, compared with 44% last month.
It has potentially huge implications extending into the fall. Remember that independents are the largest and fastest-growing segment of the electorate -- reaching an unprecedented 40% in the most recent Gallup Poll.
Independents outnumber Democrats or Republicans and how they swing will determine the winner of the next election.
In the past, Romney's trump card was his alleged electability.
Armed with his experience getting elected as a Republican in Massachusetts, the argument was that he had a proven ability to appeal to centrists and swing voters.
In contrast, the president had a demonstrated vulnerability with independents, after winning them by 8 percentage points in 2008. As I've written here before, independents started breaking with Obama early in his administration after the stimulus bill passed along partisan lines.
The disaffection deepened after health care reform took center stage.
This had long been a Democratic priority, but it had not been a centerpiece of the campaign, and independent voters were focused first on the economy. Taken together, the growth in government spending, the increase in deficits and the growing polarization in Washington turned independents off. This was not the hope and change for which they had voted. The result was that independents swung to Republicans by a 17-point margin in the midterm 2010 landslide.
But Republicans' ideological overreach since taking control of Congress has inspired a backlash among independents that Obama is now benefiting from. Even with Congress having an all-time low 11% approval rating according to CNN polls, congressional Republicans are the least popular species in the Washington swamp among independents. As a result, independent voters are open to giving Obama another look, especially when presented with the prospect of conservatives having unified control of government. But the problem is most pronounced with Romney.
Romney's poll numbers have been in free fall with independents since scrutiny of the primaries began in earnest. The number of independents who say Romney is "honest and trustworthy" has declined from 53% to 41% since November. The avalanche of negative advertising deployed with devastating effectiveness by the Romney campaign and it supportive super PAC in Iowa and Florida has taken a toll.
Likewise, only 32% of independents say Romney takes consistent positions on issues. And perhaps most devastatingly, only 31% of independents say Romney "understands the needs of people like you" -- 60% disagree. This spells special trouble for the GOP if the key battleground demographic of the election is middle-class voters.
Among the rationalizations offered by Republican political consultants is that the Democrats had a protracted primary fight four years ago, and it left candidate Obama stronger to fight and win the general election.
But there is one big difference. The 2008 Democratic contest between Obama and Hillary Clinton was focused on which candidate could better connect with centrist Democrats, especially white working-class voters who often are the decisive swing voters in a general election. As a result of that extended effort, it's no wonder that the Democratic nominee was in a better position to compete for those votes in the fall.
The problem is that the Republican contest is focused in the opposite direction -- seeing which candidate can best connect with the conservative base. Centrist Republicans and swing voters are not part of the conversation in the GOP primaries -- in fact, they are being actively campaigned against instead of courted. The greatest insult that can be hurled in this far-right field is that a candidate ever worked with Democrats in the past. The word "moderate" itself has become an insult.
This is what happens when a political party burns down the big tent.
The problem of ideological polarization, combined with an extended primary, results in candidates who have a hard time connecting with the rest of the electorate when the nomination is done. At a time when many independents are sick of the hyper-partisan gridlock in Washington -- the childish inability of too many in Congress to reason together and solve problems in the national interest -- the current fight for the far right only seems to guarantee more of the same.
To be clear, Obama is benefiting by comparison to the Republican field. His budget essentially ignores the kind of long-term deficit reduction that motivates many independent voters.
So there is no reason for overconfidence on the part of his Chicago-based campaign.
But the fight for the right that is now the focus of these primaries is souring independents on the GOP. And the relentlessly negative ads from the Romney camp are having a particularly pronounced impact on his ability to connect with the crucial independent vote, even if he were to slog through this mud fight to win the nomination.
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The opinions expressed in this commentary are solely those of John Avlon.