Tampa, Florida (CNN) -- Is the tea party changing the Republican Party from the inside -- or selling out to the GOP?
As Republicans prepare to officially roll out Mitt Romney as their party's presidential nominee at the Republican National Convention this week, major tea party groups and figures have descended on Tampa, Florida, to schmooze with party bigwigs and rally for Romney.
But Romney's conservative credentials have long been viewed with suspicion by the movement. So it came as a surprise when, before at least one event, tea party organizers committed what some activists would consider heresy: seeking approval from establishment Republicans to rally.
All of it has opened up a once unthinkable charge: the movement that's rabble-roused and rocked the GOP establishment since 2009 is now too cozy with it.
"The top national groups have already sold out," said Judd Saul, a prominent Iowa activist associated with the Cedar Valley Tea Party. "They don't truly represent the grassroots."
"Even before the caucuses, these guys were all pushing for Romney even when the primaries were going on," Saul added.
"It's a pretty widespread (sentiment). A lot of activists have noticed that."
But presidential historian Douglas Brinkley doesn't see this phenomenon as anything new.
"I think it happens all the time in politics," said Brinkley, a political analyst and professor at Rice University. "The grassroots people are the people who are hypermotivated. They are people willing to go to rallies and hold bake sales and ... and they're always later kind of seen as auxiliary players once it gets to the main game when the elections come in the fall."
"I think selling out is too strong," added Brinkley. "But you can say something to the effect of they've tricked the tea party movement into believing they were going to have a meaningful role in the 2012 election."
Others are taking their groans to social media.
"I think it is time not only to clean up Washington but we as well need to clean up or clean out the top dogs in the RNC that are turn coats," tea party supporter Margaret Robinson posted on the Facebook page for theteaparty.net. "Not only TAKE BACK AMERICA but also need to TAKE BACK OUR REPUBLICAN PARTY. "
Saska Mare, who describes herself as a "tea party Republican" and Newt Gingrich supporter, wrote: "Now is the time for All Good Patriots to come to the aid of their Country and QUIT MITT & RECRUIT NEWT!!"
The president and CEO of one of the largest tea party sponsors knows that not everyone is happy with the commingling between the two groups.
"There's always purists in any movement who think that anything less than perfect is a sellout," said Matt Kibbe of FreedomWorks, based in Washington. "But that's not how the American system works. "
The head of another group was more blunt.
"Anyone at this point who is trying to disrupt the convention or protest the nomination of Romney is blinded by irrational enthusiasm," said Dustin Stockton, chief strategist for theteaparty.net.
There is one problem with such rationalities: They contradict the movement's belief that to change the system, it must be blown up.
Since its birth three years ago, tea party activists have railed against compromise, leaned on lawmakers, launched RINO hunts against moderates deemed "Republicans in Name Only" and sought swift action on their ideas of reduced government spending, lower taxes and increased adherence to the constitution.
For them, political patience was not a virtue.
But since then, the tea party has gradually moved from anger and impatience toward acceptance and embrace. Several leaders say they understand the slow pace of change and stress the need to change the political system from the inside.
Stockton's group sponsored a rally on Sunday in Tampa, a few miles away from the GOP convention site, featuring prominent tea partiers Herman Cain and U.S. Rep. Michele Bachmann, both former presidential candidates.
The 30-year-old tea party leader is adamant that the event's goal is to continue advocating for the tea party.
"We wanted to make sure that when (activists) tune in to the convention and the convention starts, they know that the tea party is still here -- still fighting for the values they believe in," Stockton said. "Because that's really uniting more than Republicans, actually the American people in general. And we wanted to do it right before the conventions to try and set the tone for the entire convention."
Yet Stockton also revealed something that will surely cause some activists to fume.
"In order to get the venue and everything, we did get the blessings of the Romney camp and the RNC to hold the event months ago," Stockton said. "And the Romney camp is sending (Utah) Congressman Jason Chaffetz as a surrogate for Romney. So they're on board with it. "
Many tea partiers support efforts to unify the movement with the GOP.
Kibbe's group is also holding GOP-friendly events during the convention week. But he, too, beats back any notion that the tea party is toeing the Republican line.
"I would describe us as having a foot in the door and a seat at the table," the FreedomWorks chief said. "Things are definitely trending in our direction."
Kibbe also noted another achievement: the GOP embrace of core tea party proposals.
FreedomWorks had pushed the RNC's platform committee to adopt 12 items.
"We had a whole delegation of tea partiers at the platform committee," Kibbe said. "And we feel like we made a lot of progress. We feel like we had success on 11-and-a-half of them."
Sal Russo, chief strategist for the Tea Party Express, also claimed that the Republican Party is coming around to the tea party -- not the other way around.
"We have a huge Tea Party Express rally (in Tampa). In fact, we already have 15,000 reporters sign up to be there. We've called it the '2012 Republican National Convention,' " Russo joked.
Though Stockton is promoting unity during convention week, he has a special gripe: one prominent tea partier is not on the speaking list.
"I'm incredibly frustrated at the speaker lineup -- it doesn't include Sarah Palin," Stockton said. "And Palin should have definitely been invited. He also lamented that two former presidential hopefuls in 2012, Newt Gingrich and Texas Gov. Rick Perry, will not have a prominent presence.
Meanwhile, after long viewing Romney as a suspect conservative, how are activists feeling about him now?
"I say there's a solid 50-50 split within the movement" for and against Romney, Saul said.
He added: "I will hold my nose and pull the lever for Romney. Legitimately, I think that President Obama is the worst of the two evils. And Romney has a shot. And with some backing and some pushing, he could do some better things for the economy and the country. "
But the FreedomWorks chief stressed political patience.
"The practical reality of presidential politics: it takes years to build your brand, and your machine, your ability to fundraise," Kibbe said. "And the tea party class was very green; they weren't ready."
In the face of some activist criticism, Russo said the movement should celebrate a milestone.
"I think (the tea party) has successfully yanked the Republican Party back to where it's sort of always been since Reagan yanked it back -- which is an opposition to an increasing size, cost and intrusiveness of the federal government," Russo said.
Calling tea party opposition to Romney and the RNC "silly," Russo said: "I mean, sometimes people don't know when to declare victory."