A total of 1,568 registered Democrats or Democratic-leaning voters were asked about the Democratic presidential field. Those results have a margin of error of +/-2.5 percentage points. Likewise, 1,382 Republicans or GOP-leaning independents were surveyed on that party's candidates, and their results have a margin of error of +/-2.6 percent.
Overall, the Democratic contest has been very stable for months with the top four candidates fairly evenly spaced out. In the four-poll aggregation, Hillary Rodham Clinton drew 35 percent of the Democratic primary vote, Barack Obama 24 percent, John Edwards 15 percent, Bill Richardson 3 percent, Joseph Biden 2 percent, and everyone else 1 percent or less.
Among African-Americans, Clinton and Obama were essentially tied, with 40 percent and 38 percent, respectively. Clinton's lead among whites bulged to 12 points and among Hispanics to 24 points. Clinton barely edges out Obama among men, 29 percent to 26 percent, but really runs up the score with women, leading by 16 points.
Obama continues to need to expand his support beyond young and well-educated Democrats and Democratic-leaning independents. He led Clinton by 3 points within the 18-to-34 age group. But the tables turn with older Democrats: Clinton wins among those ages 35 to 49 by 13 points, those 50 to 64 by 19 points, and those 65 and older by 13 points. Similarly, Obama has a 2-point lead among those with college degrees, 29 percent to 27 percent, but Clinton runs ahead by 12 points among those with some college and by 25 points among those with just a high school education.
Finally, Obama runs basically even with Clinton among independents who lean Democratic, 27 percent to 26 percent, but Clinton sports a 17-point lead among Democrats. If these patterns sound familiar, that's because they resemble the support profiles of Gary Hart in 1984, Paul Tsongas in 1992, and Bill Bradley in 2000. The numbers are splashy and significant but not sufficiently broad-based to capture a nomination.
The stability of the Democratic contest isn't found on the Republican side. There, the combined results confirm that the field is flattening, with support levels for front-runners Rudy Giuliani and John McCain dropping at a 45-degree angle for several months. Meanwhile, Fred Thompson's numbers have skyrocketed, and support for Mitt Romney has been rising steadily. In the combined polls, Giuliani's once broad lead is now just 4 points, 25 percent to McCain's 21 percent. Thompson is third with 12 percent, and Romney is fourth with 10 percent. All others have 2 percent or less.
Giuliani's performance is especially strong among those ages 18 to 34, where he pulls 36 percent, 19 points more than McCain in second place. In his native Northeast, Giuliani draws 35 percent, 13 points more than the senator from Arizona.
McCain's 21 percent showing overall is buttressed by pockets of strength among those ages 35 to 49, where he pulls 27 percent, 4 points more than Giuliani. Among those with a high school education, McCain gets 26 percent, 3 points more than the New Yorker.
Thompson's 12 percent incorporates something of a gender gap. He runs a competitive third among men, with 17 percent, but gets only 7 percent of the female vote, coming in behind Romney. Thompson's other strength is in the South, where he scores 17 percent, compared with 11 percent in the Midwest, 10 percent in the West, and 8 percent in the Northeast. Romney's support is strongest among college graduates, where he pulls 12 percent, and in the West, where his support jumps to 17 percent, compared with 12 percent in the Northeast, 10 percent in the Midwest, and 5 percent in the South.
Neither of these contests is over, of course, but the volatile Republican race has yet to settle into a familiar or predictable pattern.