Campaign commercials for John Bel Edwards win awards

Republican U.S. Sen. David Vitter, right, and Democratic Gov. John Bel Edwards on the campaign trail in 2015.

The Democrats are given a decent chance of regaining control of the U.S. Senate this year, and they might logically expect Louisiana help them do it.

This, after all, is where the Democrats made their last stand. The Republicans did not complete their sweep of Deep South Senate seats until Mary Landrieu lost to Bill Cassidy two years ago.

Louisiana's other Senate seat is now falling vacant with the retirement of David Vitter, who was supposed to transition effortlessly into governor but got thrashed in last year's election by John Bel Edwards. It is unlikely that Vitter flopped because voters decided they wanted more liberal government; his knack for provoking dislike across party lines probably caught up with him at last. Regardless, Democrats had until then seemed locked out of statewide office indefinitely, and were greatly encouraged to receive a new lease of life, even though they had Vitter to thank for it.

If Democratic chances are improved when one of their own is governor, they might also this year find encouragement in the presidential election.

Monday's debate provided fresh confirmation that Donald Trump was a disastrous choice for the Republicans, and will likely lack coattails for Republican candidates on the same ballot. Democrats need a net gain of just four seats for the 50-50 split in the Senate that will give them control if Tim Kaine is vice president.

But Louisiana is not among the states where a Democrat might be swept into the Senate on an anti-Trump tide. Trump could not possibly make a big enough fool of himself on the campaign trail to get beaten by Hillary Clinton here; the presidential race is a foregone conclusion and thus of limited impact down the ballot.

The burning question here is not whether we will still have two Republican senators, but whether we will have two Republican senators who are also doctors. It depends on who becomes junior senator to Landrieu's successor, Dr. Bill Cassidy.

The top two in the polls for Vitter's seat are both Republicans, but the leader John Kennedy, being state treasurer, will know much more about defeasance than disease. GOP medical men are in close attendance, however, with Charles Boustany and John Fleming both seeking to emulate Cassidy and win promotion from the House to the Senate.

Boustany is close behind Kennedy in second place, and Fleming is polling in fifth. Sandwiched between them are two Democrats, lawyer Caroline Fayard and Edwards' choice, Public Service Commissioner Foster Campbell. With no Vitter to help their cause this time, Democrats will not expect to repeat Edwards's success. That must be regarded as a flash in the pan, and the best they can hope for this time is that one of their candidates will not perish until the runoff.

Now that the election is less than six weeks away, polls are finally measuring firm preferences, and offer reliable clues as to the outcome. The winner will come from the current top four Republicans in the polls, any one of whom would relish a faceoff with a Democrat.

With the polls suggesting that the runoff will likely feature Kennedy and Boustany, however, preparations are underway for such a contingency. Kennedy's campaign, by text and email, made sure that nobody was unaware of a book just published that claims Boustany consorted with one of eight prostitutes who wound up murdered in Jefferson Davis Parish a few years ago.

While there was no suggestion that Boustany was involved in any murder, hanging out with hookers would have been pretty reckless behavior for a sitting congressman. Still, as Vitter has shown, that by no means rules it out.

Boustany has denounced the book as “scurrilous lies,” and has evidently not been much hurt by it, since the poll that put him just behind Kennedy was conducted after it was published.

That doesn't mean voters think Boustany has been unjustly accused, however, for, even if they believe a politician has been hiring hookers, they may not regard that as a reason to oust him. Vitter, after all, had no trouble hanging onto his Senate seat even after it became known that he divided his time between delivering sanctimonious speeches on Capitol Hill and letting it all hang out with call girls.

His party's grip on Louisiana's senate seats appears unbreakable; the Democrats must look elsewhere.