Gearing up for a do-or-die runoff against U.S. Rep. Bill Cassidy, U.S. Sen. Mary Landrieu told supporters she now has the race she wants.

She has a point, but only given the alternatives.

That Landrieu lives to fight another day — or 32 of them — is basically a quirk of Louisiana’s open primary system and the refusal of tea party candidate Rob Maness to bow out. With three frontrunners on the ballot, nobody won an outright majority, which saved Landrieu the likely fate of so many of her colleagues and fellow Democratic hopefuls. Their numbers were nothing short of dreadful. Among potentially vulnerable incumbents, only New Hampshire’s Jeanne Shaheen and Virginia’s Mark Warner survived, barely. Elsewhere, Democratic senators lost in North Carolina, Colorado, Alaska and Arkansas (where incumbent two-term senator Mark Pryor didn’t even clear 40 percent), while embattled Republicans swatted away challengers and open seats fell into GOP hands.

To the extent there’s more good news for the three-term senator following her 42 percent showing at the polls, it’s that the Democrats have already lost control of the chamber, which is at least better than having the whole matter rest on her fate.

So while Landrieu can no longer contend that Louisiana needs to put party aside and help her keep her chairmanship of the all-important Energy and Natural Resources Committee — that, thanks to the big Republican wave, is already gone — at least Cassidy can’t keep arguing that a vote for Landrieu is a vote for Harry Reid as majority leader. That, too, is now moot.

Instead, she can make a pretty good case that the election is basically about the state-specific issues where she has an undeniably proven record — and also still about seniority. Sure, her fellow senator David Vitter will now become chairman of the Small Business Committee — which Landrieu happened to chair before her promotion earlier this year to Energy — but Vitter’s angling to become governor. If Cassidy wins and Vitter triumphs next year, she can argue, Louisiana goes to the end of the line.

That said, there’s a pile of bad news for the senator.

Forty-two percent, in what was essentially a referendum on Landrieu, her party and her party’s president, makes for a difficult starting point.

Sure, Cassidy’s even less impressive 41 percent suggests he hasn’t won voters’ hearts, which isn’t really surprising given that he basically put all his eggs into the anti-Reid-and-Obama basket. But he’s got the advantage of being the obvious option for Maness supporters. CNN’s exit poll of those who cast ballots asked what they’d do in a runoff, and 51 percent said they’d go with Cassidy, compared to 43 percent for Landrieu. Four percent said they’d stay home.

For a sense of just what she’s up against, consider a few more exit poll numbers. Landrieu courted not only the African-American voters who make up a major part of her base. She also made a big push to attract women, including white women, by talking about safety-net issues and pay equity and holding big voter events aimed at female voters around the state.

But while she won 94 percent of the black vote, she drew only 18 percent of the white vote and 22 percent among white women. In 2008, according to CNN’s exit poll, she got 33 percent of the white vote and 34 percent from white women. That’s a pretty devastating drop-off.

Another sign of trouble: Despite her frequent assertions of independence, 57 percent said Landrieu agrees too often with President Barack Obama, whose approval rating in the poll was just 40 percent.

At her election-night gathering in New Orleans, Landrieu wasted no time trying to shift the focus to the candidates and away from the president. She challenged Cassidy to no fewer than a half dozen face-to-face meetings — good luck with that, given that Cassidy has already made his reluctance to debate abundantly clear — and declared that “you’re going to have to say, Mr. Cassidy, more than President Obama’s name in these six debates.”

Cassidy, who took the stage at his own Baton Rouge party before Landrieu had finished speaking, did just that.

“The people of Louisiana have sent a signal tonight that you want a senator who represents Louisiana, not Barack Obama,” Cassidy said.

Sure, this will be a different election, and the Dec. 6 electorate will be different too, if only by degree. As much as things have changed — and as much as Landrieu would like them to — we seem to be in for another month of more of the same.

Stephanie Grace can be contacted at sgrace@theadvocate.com. Read her blog at http://blogs.theadvocate.com/gracenotes. Follow her on Twitter, @stephgracenola.