In Obama's case, 44 percent hold each view with 12 percent undecided, Rasmussen Reports said. With Perry, the current frontrunner for the Republican nomination, the split is 36 percent with 28 percent undecided.
Former Massachusetts Gov. Mitt Romney, another 2012 Republican presidential contender, is more generally seen as a moderate. In his case, 48 percent say he is mainstream, 26 percent say he is extreme and 26 percent are undecided.
In the case of U.S. Rep. Michele Bachmann, R-Minn., a Tea Party favorite in the Republican race, 51 percent of those surveyed described her as extreme, 27 percent as mainstream and 22 percent are undecided. Libertarian U.S. Rep. Ron Paul, R-Texas, is viewed as extreme by 52 percent with only 17 percent saying he is mainstream and 32 percent undecided.
There has been little change in the past year in the way voters view Obama, Rasmussen said. In 2010, 48 percent said he was mainstream and 42 percent extreme.
Rasmussen polled 1,000 likely voters by telephone on Sept. 6 and Sept. 7. The margin of error is 3 percentage points.