Harry Reid won’t be on the ballot in the U.S. Senate election in Louisiana this fall, but Republicans nonetheless want to put him in the minds of voters when they head to the polls.

The question is, how effective is that strategy?

As leader of the Democratic majority in the Senate, Reid controls the flow of legislation and is a favorite whipping boy for frustrated Republicans. In counterpoint, he has emerged as a principal Democratic flogger of “obstructionist” Republicans, who hold enough seats to block most bills under Senate procedure.

Republicans devoutly wish to take over the Senate this fall to add to their rule over the U.S. House. One of their main Democratic targets is Mary Landrieu, who’s running for a fourth Senate term in what has become a deeply red state.

To press the point that a vote for Landrieu is a vote for Reid’s continued suzerainty (and ongoing Democratic control of the Senate), Republicans recently circulated a video clip of a “Morning Joe” interview with Landrieu in which she said she would vote to re-elect Reid as majority leader, should it come to that.

And in the news release announcing the endorsement of Republican Sen. John Cornyn, of Texas, for U.S. Rep. Bill Cassidy, of Baton Rouge, the Republicans’ leading Senate challenger, the Cassidy campaign led off Cornyn’s quote with, “The reason why I’m so excited about this Senate race, here in Louisiana, is that it could well be the tipping point between Harry Reid continuing to be the majority leader of the United States Senate, or conversely new management.”

Reid, said Ben Voelkel, Republican National Committee spokesman in Louisiana, “is on the news every evening.”

Maybe so — though it’s a good bet Reid, who is from Nevada, isn’t a household name in Louisiana.

The Reid angle may work best with a narrower audience.

“It’s a good strategy in the sense that the people who pay most attention to this — the extreme partisans, the people most engaged — they know the name,” Tulane University political scientist Brian Brox said.

Pointing out Landrieu’s support for Reid “is the kind of thing that’s going to engage Republican voters and engage Republican donors,” he said. “So it’s a good thing to throw at the base.”

The issue of control of the Senate could be thrust onto center stage in Louisiana, depending on what happens Nov. 4. That’s when voters across the country will decide the fates of most U.S. Senate candidates — but in Louisiana, they may just be getting started.

With no primaries in the state before Nov. 4, the come-one-come-all election that day will function as the Senate primary for the Republican field, which also includes retired Air Force officer Rob Maness, of Madisonville, and state Rep. Paul Hollis, of Covington. Unless one candidate wins more than half the vote then, the top two finishers — likely Landrieu and the leading Republican — would head to a runoff Dec. 6.

There are three scenarios for a runoff — and two of them are bad for Landrieu, says Shreveport native and national political commentator Charlie Cook.

Republicans need to pick up six seats to win Senate control. The best scenario for Landrieu, Cook said, is for the Republicans to gain fewer than five seats Nov. 4; then her party will remain in charge no matter what happens in Louisiana, and her re-election will maintain her as chairwoman of the Senate Energy and Natural Resources Committee, with far more influence than her opponent could provide.

A not-so-good scenario for Landrieu is for Republicans to win the six seats they need Nov. 4. She will lose her chairmanship, removing one of her main arguments for returning her to the Senate.

But the worst scenario for her, Cook said, is if control of the Senate hangs in the balance Dec. 6.

In that case, he said, “Louisiana just becomes a generic Democratic and Republican race, and (Republicans will ask), ‘Do you want Obama and Reid to control the Senate?’ ”

That election, Cook said, would be very difficult for Landrieu to win.

Gregory Roberts is chief of The Advocate Washington bureau. His email address is groberts@theadvocate.com. Follow Gregory Roberts on Twitter @GregRobertsDC