Washington (CNN) - If you need more evidence that the storyline in the race for the GOP presidential nomination has dramatically changed in the past couple of weeks, all you have to do is look at the three newest national polls in the Republican horse race.
All three surveys indicate that Texas Gov. Rick Perry is dropping, businessman and former Godfather's Pizza CEO Herman Cain is rising, and former Massachusetts Gov. Mitt Romney is holding steady.
Lets start with the CBS News poll, released Tuesday evening, which indicates Romney, who's making his second bid for the White House, and Cain are tied at the top of the field, each with the support of 17% of Republican primary voters. Perry, the former front-runner in the national polls, is in third, at 12%, with former House Speaker Newt Gingrich at 8%, Rep. Ron Paul of Texas is at 7%, he's making his third run for the presidency, Rep. Michele Bachmann of Minnesota at 4%, former Sen. Rick Santorum of Pennsylvania at 3%, and former Utah Gov. and U.S. ambassador to China Jon Huntsman at 2%.
According to the survey, Romney's up one point since the last CBS poll from two weeks ago, but Cain has skyrocketed 12 points and Perry's plunged 11 points. The new poll comes after Perry's come under attack from the rival campaigns over his stance on illegal immigration, border security, and social security, his uneven performance in the last GOP presidential debate two weeks ago, and his poor showing at a much watched straw poll in Florida a week and a half ago.
The survey indicates that tea party supporters, who are very influential when it comes to picking the next GOP nominee, are one reason behind the change in the numbers.
"Tea Party backers have shifted this race: they've now thrown more support behind Herman Cain, pushing him up into a first-place tie, and away from former frontrunner Rick Perry," says the CBS News poll release.
The survey also indicates that 32% of Republican primary voters say Romney has the best chance of beating President Barack Obama in 2012 to win the White House, with 21% saying Perry has the best odds and just 8% indicating that Cain would be the best candidate to win the White House.
Cain's rise and Perry's drop are reflected in two other surveys that released earlier Tuesday. According to a Quinnipiac University poll, Romney's at 22%, with Cain at 17% and Perry at 14%. And an ABC News/Washington Post survey indicates Romney at 25% and Cain and Perry at 17%.
The CBS News poll was conducted Sept. 28-October 2, with 1,012 adults, including 324 likely GOP primary voters, questioned by phone. The survey's sampling error for likely GOP primary voters is plus or minus six percentage points.
The ABC News/Washington Post poll questioned 1,001 national adults by telephone, with a sampling error of plus or minus six percentage points for questions only of Republicans and independents who lean toward the GOP.
The Quinnipiac University poll questioned 2,118 registered voters, including 927 likely Republican primary voters, with a sampling error of plus or minus 3.2 percentage points for GOP questions.