Rep. Michele Bachmann has taken her first lead in a national poll of 2012 Republican presidential candidates, overtaking Mitt Romney by a point in a poll released Tuesday.

Bachmann leads Romney 21-20 in the latest poll from Public Policy Polling. While that's still within the margin of error, it's a big sign that she is catching fire in more than just the early primary states.

Tim Pawlenty, meanwhile, is back in seventh at 5 percent, behind Bachmann, Romney, Rick Perry, Herman Cain, Ron Paul and Newt Gingrich. He leads Jon Huntsman.

Bachmann's top ranking is dependent on who else enters — or doesn't enter — the presidential race. Bachmann leads if Texas Gov. Rick Perry is included, but she trails Romney 20-16 when 2008 VP Sarah Palin is thrown in the mix.

Of Palin voters, 44 percent say they'd back Bachmann if the former Alaska governor doesn't run, compared to just 6 percent for Romney.

In a head-to-head matchup between Bachmann and Romney, the poll found Bachmann leading 44-41, with 15 percent undecided.

For Pawlenty, Tuesday's poll is yet another where he's failed to move out of single digits. Public Policy Polling said Monday it was dropping Pawlenty from state general election polling against President Obama because the firm is only using the top five GOP hopefuls. They will keep him in their GOP primary polling.

Read the full results below:

PPP Release National 0719