MILWAUKEE (AP) -- A new poll shows President Barack Obama easily leading each of his four Republican rivals in Wisconsin.

A Marquette University Law School poll released Wednesday shows Obama leading former Sen. Rick Santorum, 51 percent to 40 percent, and leading former Gov. Mitt Romney, 53 percent to 38 percent.

The poll questioned 716 registered Wisconsin voters from Feb. 16-19.

Against Rep. Ron Paul, the poll shows Obama leading 52 percent to 36 percent, and the president holds a lead over former House Speaker Newt Gingrich, 56 percent to 33 percent.

Santorum is the early favorite in Wisconsin's Republican primary April 3. The poll shows him with 34 percent, while Romney gets 18 percent. Another 17 percent say they're undecided.

The overall margin of error is plus or minus 3.7 percentage points.

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