Might abortion still be the undoing of the Rudy Giuliani campaign? According to Pew Research, among Republican voters, less than half - 43 percent - are aware of Giuliani's pro-choice position on abortion, which is out of step with the Republican mainstream. Moreover, says Pew, "just 44 percent of Republican voters who cite abortion as a very important issue can identify Giuliani as the candidate who supports a woman's right to choose. However, nearly twice as many Republican and Republican-leaning voters who rate abortion as very important say there is no chance they would vote for Giuliani, compared with those who view abortion as less important (27 percent vs. 15 percent)."
The upshot: as the other 57 percent of Republicans become aware that Giuliani is not just passively pro-choice but actively favors government funding of abortion, might the number of Republicans determined to vote against Giuliani rise? Is his current position in most polls - supported by no more than a third of the GOP electorate - be Giuliani's ceiling?
And if so, who might begin to chip away at his support?
The Pew data suggests it could be Fred Thompson. Here's why: An equal percentage of Republicans who have heard of either candidate - 37 percent - currently say there is a "good chance" they would vote for Giuliani or Thompson. That's 13 percentage points higher than Mitt Romney and 17 points of either John McCain or Newt Gingrich.
And among Republican voters who considered abortion, terrorism, immigration, taxes or Iraq to be "very important" issues, Thompson leads Giuliani in four of the five categories, trailing him by just one point among voters who consider Iraq to be a "very important" issue.
Among Republican voters who think abortion is very important, Thompson leads Giuliani by seven points, 39-32. On the other issues, it is 41-40 for Thompson on terrorism, 41-36 for Thompson on immigration, 42-40 for Thompson on taxes, and 39-38 for Giuliani on Iraq.
(Romney doesn't crack 30 in any category, while McCain and Gingrich's numbers are mostly in the teens and low 20s.)
The bottom line number that suggests Giuliani has hit a ceiling while Thompson still has much upside potential is this: Pew found that 95 percent of Republican and Republican-leaning voters have heard of Giuliani, while only 58 percent have heard of Thompson. (94 percent have heard of McCain, 93 percent have heard of Gingrich and 72 percent have heard of Romney.)