I'd say the only thing that would make this safe D is if David Duke runs for governor again. Landrieu probably wins in a landslide and he probably wins Calcasieu and St Tammany parishes as well (which Edwin Edwards did against Duke in 1991).
Even David Duke would win Louisiana with a Democrat in the Oval Office.
Nowadays the ad campaign would probably be "Vote for the Klansman: it's important (he's a PATRIOT and supports the 2A and STRONG BORDERS)"
Duke is still really hated in Louisiana and I think the Klan aspect would be too bitter a pill to swallow for a critical mass, but it would certainly be much closer than 91.
David Vitter lost by double digits despite a Democrat as the president.
The
only people Duke could
maybe beat are Gary Landrieu or Bill Jefferson.