(CNN) -- The push poll is as much of a campaign-year staple as speeches at state fairs, as predictable as January snow in Manchester: political attacks designed as legitimate surveys.
Sen. John McCain, R-Arizona, won the New Hampshire primary in 2000.
But one of this year's came with a brutal twist, when John McCain's New Hampshire vice chairman, Chuck Douglas, accused Mitt Romney's campaign of attacking its own candidate to try to harm the reputation of the Arizona senator. "I think all fingers point to Romney," he said Thursday. He backtracked soon after -- but he's still with the campaign, despite loud calls from Romney's camp for his resignation.
That kind of verbal warfare is par for the course in the bitter blood feud between Republicans Romney and McCain, just days before New Hampshire's presidential primary vote.
Both men have a logical claim to victory in the Granite State that could make a loss very tough to recover from: Romney was the governor of neighboring Massachusetts, while, McCain won the GOP primary here in 2000. Right now, McCain leads him 33 percent to 27 percent in the CNN/WMUR poll released Saturday.
This confrontation has been years in the making. The pair's animosity didn't begin with Romney's first New Hampshire attack ad last month, or McCain's recent New Hampshire surge that left the two men roughly neck-and-neck in most primary race surveys. It didn't start when they tangled at the CNN/YouTube debate over the definition of torture, or when McCain essentially swept New Hampshire's newspaper endorsement race. Watch the Iowa/New Hampshire disconnection »
In fact, aides to both men were trading public insults, and bashing the other's candidate -- often in starkly personal terms -- years before either officially announced their White House intentions. Tuesday's showdown is the perfect storm of personal animus and political reality.
The feud is, according to aides, partly driven by small but significant ideological differences, partly fueled by personality.
But the political has consistently mixed with the personal. As far back as two years ago, when Romney announced he would not seek a second term as governor, he jokingly cited McCain as a cautionary example of the career politician mindset he wanted to avoid.
Despite McCain's front-runner status early in the race, Romney's aides insisted he didn't have the political muscle to hold on to President Bush's most influential supporters. Even more infuriating for the McCain team, they cracked jokes about the senator's age -- a sore spot, since the Arizona Republican would be the oldest first-term president in history.
The antipathy was mutual. McCain staffers often mocked Romney as a political newbie, and a lightweight candidate who would never be able to withstand the cut-throat primary process. And throughout 2006 and 2007, the McCain team fostered the portrait of Mitt Romney as a "flip-flopper."
As the senator struggled with campaign cash woes and staff cuts that pulled him out of the race's top tier, his staff was unable to stem Romney's early momentum. The rivalry seemed to slip off the front burner as the former Massachusetts governor focused his fire on new threats, like Mike Huckabee.
But as McCain's late surge in New Hampshire sparked an attack ad from the Romney camp, the rhetoric has reached the boiling point. With both men locked in a battle for political survival, their teams are trading negative press releases and brutal Web ads almost hourly.
In the past few days alone, senior McCain aide Mark Salter called Romney a "small varmint gun-totin', civil rights-marching, NRA-endorsed fantasy candidate." And a steady stream of attack ads culminated this weekend in a Web spot from the Romney camp that said McCain "twists the truth like Clinton." Republican primary race rhetoric may not come much more brutal than that. E-mail to a friend