WASHINGTON -- Senate Republicans' refusal to even consider a Supreme Court nominee is "shocking," Sen. Elizabeth Warren (D-Mass.) said Wednesday, accusing the GOP of caving to extremists.

Warren delivered that message on the Senate floor after a number of Republicans reiterated their intention to ignore any nomination President Barack Obama makes to replace the late Justice Antonin Scalia.

Not long before Warren Spoke, Sen. Tom Cotton (R-Ark.) had argued that taking up a nominee would trample the Constitution because Obama is a "lame duck president with a stale mandate."

Warren denounced that position in an impassioned speech of her own, saying that exactly the opposite was true.

"The message from Senate Republicans is crystal clear: Forget the Constitution," Warren said. "Their response to one of the most solemn and consequential tasks that our government performs, the confirmation of a Supreme Court justice, will be to pretend that that nominee and President Obama himself simply do not exist. Cannot see them. Cannot hear them."

While Republicans have repeatedly argued that they are only doing what Democrats said they would do in the past, Warren said she saw it as part of a much broader attempt, beginning the moment Obama was elected, to cast him and his entire government as illegitimate.

"Since the first day of the Obama presidency, Republican senators have bowed to extremists who reject his legitimacy and abuse the rules of the Senate in an all-out effort to cripple his administration and to paralyze the federal courts," Warren said.

She pointed out senators' numerous filibusters and delays of Obama's nominees, from stalling Attorney General Loretta Lynch's confirmation for more than half a year to refusing to fill vacancies on the National Labor Relations Board and the District of Columbia Circuit, often referred to as the nation's second-highest court, for years.

"Republican extremists aren't voting against individuals based on a good-faith judgment about a specific person. No, they are blocking votes wholesale in order to keep those jobs vacant and undermine the government itself," Warren said.

Those are precisely the sort of actions that directly tie Republican Senate leaders to the party's presidential candidates -- even as they try to find anyone but business mogul Donald Trump or Sen. Ted Cruz (Texas) to take up the GOP mantle in the fall, Warren argued.

"No matter how much it damages the nation, no matter how much it undermines the courts, no matter whether it cripples the government or lays waste to our Constitution, Senate Republicans do pretty much everything they can to avoid acknowledging the legitimacy of our democratically elected president," she said.

"For too long, the Republicans in the Senate have wanted to have it both ways: They want to feed the ugly lies and nullify the Obama presidency while also claiming that they can govern responsibly," she said. "Well, that game is over."

She pointed to Trump and Cruz as reflections of Republican lawmakers, some of whom are seeking to distance themselves from the current GOP front-runner.

"Candidates motivated by bigotry and resentment, candidates unable to govern, candidates reflecting the same extremism that has been nursed along for seven years right here in the United States Senate, are on the verge of winning the Republican party's nomination for president."

Comparing the two elections that Obama won by 9 million and 5 million votes, respectively, to the one George W. Bush won in 2000 with the help of hanging chads in Florida and a Supreme Court decision, Warren said the GOP should finally deal with the extremism in its ranks by acknowledging that Obama is, in fact, the president -- and by weighing his nominees.

"If it is true that some Republican senators are finally ready to stand up to the extremism that denies the legitimacy of this president and of the Constitution, I say to you, do your job," Warren said. "Vote for a Supreme Court nominee."

"If you want to stop extremism in your party," she added, "you can start by showing the American people that you respect the president of the United States and the Constitution enough to do your job."