No one denies that Lt. Governor Mitch Landrieu is the frontrunner in the New Orleans mayor’s race. But a new poll released Wednesday by WWL-TV in New Orleans indicates the third-time candidate could be in some familiar trouble from here on in to Election Day.

Landrieu has a big lead at the moment, with 45 percent of respondents saying they’re with him. Businessman Troy Henry comes in second with 14 percent, while Rob Couhig and John Georges have eight percent each. James Perry (3 percent) and Nadine Ramsey (2 percent) bring up the rear. Nineteen percent remain undecided.

Among the internal numbers in the WWL poll, conducted by Dr. Ron Faucheux: Landrieu is polling 53 percent of whites and 40 percent of blacks, while Henry is getting 22 percent of blacks and just two percent of whites. Georges, who is spending more money than anyone in the race, is getting 10 percent of the white vote and six percent of the black vote, while Couhig is getting 16 percent of the white vote and 1 percent of the black vote. Perry (five percent of the white vote) and Ramsey (one percent) are each getting three percent of the black vote.

In a very hopeful sign for Landrieu, he’s getting 37 percent of the city’s Republicans (just shy of six percent of the total vote comes out of that number), which is a larger percentage than one would expect. But with only 51 percent of the Democrat vote going Landrieu’s way, he may be running up against a ceiling of support.

Landrieu especially needs someone other than Henry as a runoff opponent if he can’t get to 50 percent, and right now it looks like that’s not in the cards. Henry is the candidate with the best potential for growth, as with an electorate somewhere in the range of 60 percent African-American and a quarter of it still undecided he’s got a natural constituency from which to pick up support. Henry is also still a relative unknown, as 38 percent of the voters say they don’t know enough about him to have an opinion. That compares to seven percent for Landrieu, 52 percent for Couhig (who is unlikely to catch Henry given the “R” by his name) and 31 percent for Georges.

The traditional narrative about frontrunners in polls is that if they’re not above 50 percent they’re vulnerable. Landrieu, for all his advantages, is still five points shy of the magic number. And if he gets into a runoff with Henry, he runs into the same black-white demographic nightmare he faced against Ray Nagin four years ago, with the same problematic positioning on the other side – Henry, the private-sector candidate with an appeal to New Orleans’ white business community (which admittedly has not materialized to date, though with Couhig and Georges combining for 39 percent of the Republican vote and another 10 percent undecided he has potential with that group) can play the exact same double game Nagin did – stoking the racial differences in the black community while castigating Landrieu as a hard-core lefty among the white community.

The interesting question now is whether the candidates at the bottom and middle of the heap will continue in the race, or where their support will go in the runoff. Couhig won’t quit, since  as the only Republican in the race he has a standard to carry. Georges’ arrogance and deep pockets might keep him in the race,  though he’s clearly not gaining the ground necessary to catch Henry to make the runoff. Perry and Ramsey’s support will in all likelihood move to Henry, or at least most of it will. It’s reasonable to assume that Henry is going to pick up the majority of the undecideds barring a major gaffe, because if Landrieu hasn’t made a case to vote for him by now one wonders whether it’s possible for him to ever do it.

In the end, Henry’s fate will depend on whether he can reel Couhig and Georges in as endorsers. Landrieu’s best hope is to drive a wedge between those two and his closest competitor, without agitating his black support. It’s a dicey proposition, and one with very high stakes for a politician who has seen his mayoral dreams collapse before near the finish line.