Sen. Mary Landrieu, D-La., acknowledges supporters at her election night headquarters in New Orleans, Tuesday, Nov. 4, 2014. Landrieu is in a runoff with Republican Senate candidate, Rep. Bill Cassidy, R-La. (AP Photo/Bill Haber)

Sen. Mary Landrieu (D-La.) has participated in a keg stand. She has run this desperate ad. She lost an energy committee chairmanship that she often touted, when the GOP took the Senate on Nov. 4. She has clashed -- in front of reporters -- with a leader of her party. That same party basically abandoned her in her runoff campaign for a fourth term.

But on Tuesday, she suffered the biggest indignity of her 2014 campaign, and possibly of her political career.

Landrieu, reduced to a relatively pointless gambit to demonstrate her clout in Washington, failed to secure the 60 votes required to move forward with the construction of the Keystone XL pipeline. She came up one vote shy.

This was basically Landrieu's final play. With no party funding for her campaign, she has been drubbed on the airwaves -- as in, exponentially so. And even before that, few gave her much hope in her runoff with Rep. Bill Cassidy (R-La.).

So in a last-ditch effort to move the needle, she launched the Keystone campaign. Nevermind that the very same bill will probably pass with ease once Republicans take control of the Senate in January. She wanted to prove she could make it happen two months earlier -- because why not.

And Senate Democrats -- who, again, have abandoned her financially -- have now abandoned her in spirit too. The vote wasn't just meaningless because Republicans will pass the bill come next year; it was also meaningless because the White House has basically said it would veto the bill, as the State Department is still reviewing the project.

And despite all of it -- despite the whole dog-and-pony show of the past week -- Democrats couldn't even give Landrieu enough votes to breathe a little life (hypothetically, at least) into her long-shot campaign.

Bloomberg declared last week that Democrats had left "a body on the campaign trail."

On Tuesday, with Landrieu's assistance, they metaphorically ran over the body with a truck.

And Landrieu, a three-term senator and member of a royal political family from Louisiana, just proved precisely how little clout -- or hope -- she has.

In a tight vote, the Senate rejected the Keystone XL pipeline Tuesday evening, dealing a serious blow to the re-election efforts of Sen. Mary Landrieu (D-La.). (AP)