WASHINGTON, Jan. 26 (UPI) -- Massachusetts Sen. Elizabeth Warren gave an impassioned speech on the Senate floor Tuesday, which contained a possible clue about who she may be planning endorse -- or not endorse -- for the 2016 Democratic presidential nomination.
Warren's speech, which commemorated the sixth anniversary of a key Supreme Court decision that loosened campaign spending regulations, proposed a constitutional amendment to outlaw excessive spending for candidates.
"The first votes will be cast in Iowa in just 11 days. Anyone who shrugs and claims it is too hard has crawled into bed with the billionaires who want to run this country like some private club," she said. "We are headed into another presidential election, and I speak out today because I'm genuinely alarmed for our democracy."
Some analysts believe her remarks Tuesday indicate Warren will not be endorsing former Secretary of State Hillary Clinton, who has received substantial financial backing for her present bid as well as her 2008 run.
In recent weeks, Warren has been under pressure from Senate colleagues to endorse Clinton -- but that's a move that may never come.
Warren is the only Democratic woman in the Senate who hasn't backed the former New York senator. In November, she was the only female Democratic senator to skip a Clinton fundraiser, and last July she seemed critical of Clinton during a liberal convention.
Warren also has emphasized that her signature on a 2013 letter encouraging Clinton to run in 2016 was not to be construed as an endorsement.
She has promised to endorse someone, but at this point analysts aren't sure whether she will lean toward Vermont Sen. Bernie Sanders -- or perhaps someone else. What does seem clear is that the candidate of her choice will be someone who shares her desire for greater campaign spending controls.
"All of us were sent here to do our best to make government work, not just for those at the top, but to make government work for all the people. It's time we start acting like it," Warren said Tuesday. "Six years ago the Supreme Court turned loose a flood of hidden money that is about to drown our democracy. We can blame the Supreme Court. We should blame the Supreme Court."
Sanders, a fervent opponent of unrestricted campaign spending, has said his litmus test for appointees to the high court bench would be to ask whether they would overturn the decision in Citizens United v. FEC.
Clinton, though, has said she would use the same test -- and stated she would support a constitutional amendment to reverse the high court decision when she announced her candidacy in April -- the same proposal Warren pitched Tuesday.
The top three outside groups supporting Clinton, though, are super PACs. Clinton has received more than $5 million in contributions from Wall Street donors alone and has run more campaign ads in the current election cycle than anyone else, data from the Center for Public Integrity indicate.
Since the 2010 decision, Citizens United has kept after Clinton. In October, the group sued to obtain Clinton's schedules from her time as secretary of state.