Mitt Romney has a slight lead over Rick Santorum in next week's Wisconsin Republican presidential primary, according to a new NBC News/Marist poll released early Friday that also shows President Obama well ahead of his GOP challengers in the Badger State, which has not voted for a Republican for president since 1984.
Romney's lead over Santorum is seven points, 40 percent to 33 percent, roughly equal to his advantage in a Marquette Law School poll released earlier this week. Rep. Ron Paul, R-Texas, is at 11 percent, former House Speaker Newt Gingrich is at 8 percent, and 7 percent of likely primary voters are undecided.
Romney's lead comes from older, less conservative, more educated and wealthier voters. Voters under age 45 break for Santorum, 35 percent to 27 percent. But among voters 45 years of age and older, Romney leads, 45 percent to 32 percent.
Santorum leads Romney among only those voters who say they are "very conservative," outpacing the former Massachusetts governor, 42 percent to 33 percent. But Romney leads Santorum by nine points among "conservative" voters, and he has a 19-point edge among "liberal" or "moderate" voters.
Likewise, voters who "strongly support" the tea party break for Santorum, the former Pennsylvania senator, 40 percent to 32 percent. But more lukewarm tea party supporters favor Romney by 12 points, and those who do not support the tea party break for Romney by 11 points.
Romney has just a slight lead among voters without college degrees, 38 percent to 34 percent. But among college graduates, Romney leads by a significant margin, 44 percent to 31 percent.
Among voters with a household income of less than $75,000, Romney and Santorum are tied, with each candidate earning 35 percent of the vote. But Romney wins among voters making $75,000 or more, 47 percent to 32 percent.
A victory in Wisconsin's winner-take-all primary next Tuesday would cap what is expected to be an excellent day for the Romney campaign. An automated-telephone poll this week in Maryland showed Romney comfortably ahead of Santorum, and, in Tuesday's third primary in the District of Columbia, Santorum did not even qualify for the ballot. After Tuesday's slate of primaries, there is a three-week gap until the next contests on April 24.
Half of all registered voters in the state approve of the job Obama is doing as president, while 40 percent disapprove. Obama sports double-digit leads against all his GOP opponents, including a 52 percent to 35 percent advantage over Romney. In that matchup, Obama leads by 21 points among independents, 13 points among whites, 12 points among men, 25 points among women and 15 points among voters aged 60 years and older.
Santorum actually runs a few points closer, trailing Obama, 51 percent to 38 percent.
The poll also found voters evenly divided on the performance of the state's controversial Republican governor, Scott Walker, who will be challenged by Democrats in a recall election later this year. His job approval rating was at 48 percent, with 48 percent disapproving.
The NBC News/Marist poll was conducted March 26-27, surveying 2,792 registered voters. The margin of error for the full sample is plus-or-minus 1.9 percentage points. The presidential general election matchups were conducted among split samples and carry margins of error of plus-or-minus 2.6 percentage points.
The poll also included 740 likely Republican primary voters; those results carry a margin of error of plus-or-minus 3.6 percentage points.