Sen. Mary LandrieuMary LandrieuYou want to recall John McCain? Good luck, it will be impossible CNN producer on new O'Keefe video: Voters are 'stupid,' Trump is 'crazy' CNN's Van Jones: O'Keefe Russia 'nothingburger' video 'a hoax' MORE (D-La.) leads her closest Republican challenger, Rep. Bill CassidyWilliam (Bill) Morgan CassidyBen Shapiro: Who died and made Jimmy Kimmel Jesus? Dems look to turn ObamaCare tables on GOP in '18 Congress misses deadline to reauthorize childrens' health care program MORE (La.) by 3 points, according to a new poll, in a key Senate race that may be headed to a runoff.

A CNN/ORC poll released Sunday morning shows 43 percent support for Landrieu and 40 percent for Cassidy. Tea Party candidate Rob Maness was the choice of 9 percent of the respondents.

The telephone survey of 1,013 adults, conducted between Sept. 22 and 25, has a 3-percentage-point margin of error.

The Louisiana race would go to a runoff between the top two vote-getters if no candidate gets more than 50 percent of the vote in November.

Fifty percent of likely voters in the new survey said they would choose Cassidy in that runoff, compared with 47 percent who would pick Landrieu.

Landrieu and Maness each drew 48 percent support in a hypothetical runoff.

President Obama’s approval rating in Louisiana stands at 37 percent in the new poll, compared with 61 percent of likely voters who view him unfavorably.