ABC News' Amy Walter reports: In an interview with Top Line this afternoon, Adam Green, co-founder of the liberal group Progressive Change Campaign Committee, warned that if President Obama ultimately compromises with congressional Republicans to extend a temporary tax cut of all Bush-era tax cuts “he is really risking alienating his most fervent supporters.” Green: “We want him [Obama] to succeed in passing change we can believe in, which he campaigned on, but there is no room for compromise on an issue where Democrats are representing 98 percent of the people and Republicans are only standing for two percent. We need a fight, and the American people deserve that fight, which is not happening so far, but people want it. ” “And I'll tell you, as I have said before, a lot of people who worked on his campaign are members of our group and he is really risking alienating his most fervent supporters — millions of people who voted for him, but also his former campaign staffers. We have been getting emails from some of them– I will tell you what they have said. One field organizer in Nevada said, if he capitulates on this, there really is no point in voting for him in 2012,” said Green, “And another field organizer says, extending the Bush tax cuts will kill volunteer recruitment and retainment.” Last week, the PCCC launched an ad in Iowa calling on the President to “fight, don’t cave” on Bush tax cuts. The ad features video of the President in Iowa in 2007 saying that he supports letting tax cuts for the “wealthiest Americans” expire. Despite the fact that the conventional wisdom suggests that a compromise deal is already well in the works and likely to be voted on this week, Green says there’s still time for the President to make his case. “Compromise is fine after you have actually had the fight,” said Green, "We have not seen President Obama fly to Maine and rally Olympia Snowe's constituents against her or fly to Massachusetts and rally Scott Brown's constituents against him. When he does that, maybe he can come back and talk about a compromise. My guess is that if he did that, they would actually cave and he could win without a compromise." Also joining the show was Politico’s Jonathan Martin who discussed the left’s disillusionment with the President and whether or not there’s any chance that we’d see an Obama primary challenge.