House Minority Leader Nancy Pelosi sent out a dramatic, no-holds-barred fundraising email on Monday saying she is "determined to avenge President Obama if it’s the last thing I do" by preemptively opposing President Trump's Supreme Court nominee.

Pelosi, 78, is one of several top Democrats -- including Sen. Bob Casey, D-Pa., and Senate Minority Leader Chuck Schumer, D-N.Y.-- who already have announced that they oppose Trump's pick without knowing whom the president has selected. Schumer has said the Senate should not consider any Supreme Court nominees during an election year.

Meanwhile, Fox News has learned that several red-state Democrats, including three who voted to confirm Neil Gorsuch last year, will not be attending tonight's primetime rollout of the Supreme Court nominee in the White House.

In the fundraising email, Pelosi opened by acknowledging that she has been making persistent appeals to potential donors lately: "I emailed on Saturday. I emailed on Sunday. Now I’m emailing you again today."

She then outlines her plan to get back at Senate Republicans for their refusal to vote on Obama's 2016 Supreme Court nominee, Merrick Garland. That vacant seat ultimately went to now-Justice Gorsuch after Trump's election. Pelosi, though, has no actual vote in the confirmation process, and seemingly uses the email to raise money for House Democratic candidates.

"I just learned that SECONDS after Trump’s announcement... Republicans will launch an unprecedented $1.4 MILLION ad blitz to support his nominee," Pelosi wrote. "I’m worried this will eviscerate our chance to make Republicans pay for the Supreme Court seat they STOLE from President Obama."

The email, with the subject line "Trump nominee BACKFIRES," was sent by the Democratic Congressional Campaign Committee (DCCC) and signed by Pelosi.

It goes on to promise that Pelosi will "personally triple-match" any gifts to her so-called "Supreme Court fund" prior to Trump's announcement.

"I’m determined to avenge President Obama if it’s the last thing I do." — Rep. Nancy Pelosi, D-Calif.

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Pelosi's link to the Supreme Court fund takes prospective donors to a website apparently run by the DCCC. In large text, the website reads: "Democrats 2018."

Pelosi's heightened rhetoric was matched by other Democrats in the tense run-up to Trump's expected Monday night primetime announcement of his replacement for retiring Associate Justice Anthony Kennedy.

The White House hit back earlier in the day after another top Democrat vowed to oppose Trump's judicial nominee sight-unseen.

In a series of tweets, Sen. Bob Casey, D-Pa., called the nomination process "corrupt."

"I will oppose the nomination the President will make tonight because it represents a corrupt bargain with the far Right, big corporations, and Washington special interests," Casey tweeted. "Any judge on this list is fruit of a corrupt process straight from the D.C. swamp."

Casey, ostensibly a pro-life Democrat, has been supported by abortion rights groups because of his votes for Planned Parenthood and Obamacare. He has a 100-percent rating from pro-choice group NARAL.

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In response, White House Deputy Press Secretary Raj Shah called Casey's decision predictable but regrettable.

"Unfortunate (though not surprising) that even before his or her qualifications can be evaluated, Sen. Casey is refusing to even consider the President’s #SCOTUS nominee," Shah wrote.

Shah also announced that former Arizona GOP Sen. John Kyl would be the so-called "sherpa" for Trump's nominee, meaning that he will help guide the nominee through Senate meetings and other trappings of the process.

Pennsylvania, which Casey represents, narrowly went for Trump in 2016. But Casey's seat is relatively secure -- unlike the seats of other red-state Democrats, such as West Virginia's Joe Manchin, North Dakota's Heidi Heitkamp and Indiana's Joe Donnelly.

Manchin, Heitkamp, and Donnelly each were invited to the White House tonight for Trump's Supreme Court announcement, Fox News has confirmed. All three, who voted for Gorsuch's confirmation last year, declined the invitation.

"While I appreciate the invitation from the White House to attend this evening’s announcement, I declined so that I can meet first with the nominee in a setting where we can discuss his or her experience and perspectives," Donnelly said in a statement. "In the coming days, I will be reviewing the record and qualifications of the president’s nominee."

Additionally, Fox News has learned that another red-state Democrat, Alabama Sen. Doug Jones, will not attend the rollout tonight. Jones -- potentially a key vote in the upcoming nomination -- was not a senator during the Gorsuch hearings.

California Sen. Dianne Feinstein, the ranking Democrat on the Senate Judiciary Committee, and Sen. Lisa Murkowski, R-Alaska, also will not attend despite being invited, Fox News can confirm.

The embattled red-state senators likely must choose between alienating their constituents or trying to halt a conservative nominee who may ultimately prove unstoppable anyway because of the GOP's slim Senate majority.

Speaking on "Fox News Sunday," Republican Sen. Lindsey Graham called the Supreme Court nomination a veritable "nightmare" for Democrats hanging onto their vulnerable seats in states that largely support Trump.

But over the weekend, a top Democratic senator suggested that stopping the nominee is more important than the upcoming midterm elections.

Sen. Dick Durbin, D-Ill., acknowledged that so-called red-state Democrats may be tempted to vote for Trump's selection out of political necessity, but urged his colleagues Sunday to consider more than their political careers.

"Beyond the procedure, beyond the gamesmanship, it is a life-and-death important decision to be made by this court on so many issues," the Senate minority whip said on NBC's "Meet the Press."

Fox News' Serafin Gomez, John Roberts, and Chad Pergram contributed to this report.