Forty-two percent of 1,160 registered voters surveyed by Quinnipiac (Conn.) University favored an unnamed Republican challenger for president next year compared to 40 percent who prefer Obama.
Democrats favored Obama by 83 percent to 12 percent, but Republicans opposed him 84 percent to 14 percent. Independents were split.
Meanwhile, Sen. Bill Nelson, a Democrat seeking a third term, and newly elected Republican Sen. Marco Rubio enjoyed a 2-to-1 favorable to unfavorable standing.
Quinnipiac's random telephone survey taken by land line and cell phone between Jan. 25-31 had a margin of error of plus or minus 2.9 percentage points.