Democratic Sen. Mary L. Landrieu remains undoubtedly vulnerable in her 2014 re-election effort in the Republican redoubt of Louisiana.

But increasingly, it appears her future GOP opponent could also be vulnerable after an exceedingly long and divisive primary for the right to take on the three-term senator.

Last year, Republicans viewed Rep. Bill Cassidy, who has a moderate profile and flush bank account, as the consensus pick to run against Landrieu. But Cassidy has not announced his intentions yet, and now other ambitious Pelican State Republicans — including those who see themselves as more conservative than Cassidy — have been quietly expressing interest in the race.

One top GOP strategist in the state, unaligned with any potential candidate, called Cassidy’s hesitation “a big mistake” because it allows other candidates to ponder the race and keeps donors and grass-roots supporters from coalescing around him.

Among those Republicans considering Senate bids: Reps. John Fleming and Charles Boustany Jr. and former Rep. Jeff Landry.

Fleming said he was seriously considering a Senate run but hadn’t made a decision yet.

“We’re really doing the analytics right now,” he said. But Fleming noted that he had been ranked as one of the most conservative members of the 112th Congress.

Similarly, Landry said he hasn’t ruled anything in or out but was “listening” to the people in the state.

Asked about the potential Republican primary field for Senate, Landry said, “I’m not interested in having a moderate [Republican] represent me in the U.S. Senate.”

A Boustany aide said the congressman was “weighing his options.”

In the coming months, Republicans will see whether these trial balloons evolve into the full-blown blimps of statewide campaigns. But the fact that serious candidates are floating their names is a sign that Cassidy has not cleared the field.

Part of the reason: Cassidy recently parted ways with influential GOP consultant Timmy Teepell, Republican Gov. Bobby Jindal’s former chief of staff. That’s raised eyebrows in Republican circles about Cassidy’s plans.

Teepell declined to elaborate on his departure from Cassidy in an interview. But he emphasized Landrieu’s political vulnerability.

“I think it’s going to be a wide-open type of a race because she is so vulnerable,” Teepell said. “I think you may end up with a couple of congressmen running and a couple of other people running.”

One of those other people could be Chas Roemer, an elected member of Louisiana Board of Elementary and Secondary Education and the son of former GOP Gov. Buddy Roemer, according to Teepell.

Roemer didn’t return inquires from CQ Roll Call seeking comment. But unaligned GOP insiders say he is good on the stump.

Cassidy wasn’t available to comment on Tuesday. But in response to criticism from GOP operatives, Cassidy spokesman John Cummins said the congressman “isn’t worried about what other folks are saying.”

“He’s focused on reviving the economy, creating jobs and minimizing the damage of Obamacare,” Cummins said.

Even though he hasn’t made an announcement, insiders told CQ Roll Call that Cassidy has been making moves that would indicate a potential run. Cassidy’s appearances outside his district have not gone unseen.

“Cassidy is the only person I’ve noticed who is doing things outside of the district,” said a plugged-in Louisiana Republican operative unaligned with any candidate. “I do think he is the only one laying the groundwork for a campaign.”

Cassidy has been making moves outside Louisiana, too. This year, the congressman met with officials from the Club for Growth, an influential group that supports fiscally conservative candidates.

Whether and how outside groups and Louisiana political money brokers coalesce could go a long way to determining just how hard-fought the GOP’s intraparty Senate battle will be — or if there will be one at all.

At the end of 2011, the last year for which the club’s conservative scores are available, Cassidy had a lifetime score of 79 percent. Fleming had 96 percent, Landry had 94 percent and Boustany had 68 percent.

Longtime pollster Bernie Pinsonat, who has worked for candidates of both parties, said that despite all the talk, he expected the GOP field to shake out to one serious contender and also-rans.

“At this point in time, the betting money is that the Republicans will have one person who is the man or woman and the money will be behind that person,” he said.

But privately, Republicans in the state aren’t so sure. Louisiana’s “jungle” primary election law means all candidates, Republicans and Democrats, show up on the November 2014 ballot. If no candidate gets more than 50 percent, the top two finishers head to a post-Election Day runoff.

That means the primary would last months longer than any other state. As a result, Louisiana GOP operatives worried that a divisive multicandidate field would leave Republicans with a weakened — and perhaps weaker — candidate in a runoff against Landrieu.

“That’s more of the story here,” the operative said. “Is it going to be a bloodletting?”

Fleming, speaking to CQ Roll Call from Shreveport, La., on Tuesday afternoon, reflected that “both in the House and the Senate,” there had been a number of GOP primaries pitting a conservative candidate versus a more moderate one.

“I just think we’re going to tend to see more of that,” he said.