Liberal groups are mounting a major offensive against President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE’s Supreme Court pick, hoping to pressure every Democratic senator to vote against whomever the White House nominates to succeed Justice Anthony Kennedy.

With Republicans clinging to a 50-49 voting majority given Sen. John McCain John Sidney McCainThe Memo: Trump's strengths complicate election picture Mark Kelly: Arizona Senate race winner should be sworn in 'promptly' Cindy McCain: Trump allegedly calling war dead 'losers' was 'pretty much' last straw before Biden endorsement MORE’s (R-Ariz.) battle with brain cancer, Democrats also hope to pick off two Republican votes to stall Trump’s nominee.

The biggest targets are Sens. Lisa Murkowski Lisa Ann MurkowskiClub for Growth to spend million in ads for Trump Supreme Court nominee Pebble Mine CEO resigns over secretly recorded comments about government officials Maryland's GOP governor says Republicans shouldn't rush SCOTUS vote before election MORE (Alaska) and Susan Collins Susan Margaret CollinsClub for Growth to spend million in ads for Trump Supreme Court nominee Maryland's GOP governor says Republicans shouldn't rush SCOTUS vote before election The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November MORE (Maine), two Republican women who support abortion rights.

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But the odds are long.

Murkowski and Collins backed Trump’s last pick for the court, Neil Gorsuch, even though he was seen as a likely vote against abortion rights.

In addition, a handful of Democratic senators — Heidi Heitkamp Mary (Heidi) Kathryn HeitkampHarris faces pivotal moment with Supreme Court battle Centrists, progressives rally around Harris pick for VP 70 former senators propose bipartisan caucus for incumbents MORE (N.D.), Joe Manchin Joseph (Joe) ManchinManchin defends Supreme Court candidate Barrett: 'It's awful to bring in religion' The Hill's Morning Report - Sponsored by Facebook - Trump, GOP allies prepare for SCOTUS nomination this week Trump meets with potential Supreme Court pick Amy Coney Barrett at White House MORE (W.Va.) and Joe Donnelly Joseph (Joe) Simon DonnellyHarris faces pivotal moment with Supreme Court battle Trump meets with potential Supreme Court pick Amy Coney Barrett at White House Names to watch as Trump picks Ginsburg replacement on Supreme Court MORE (Ind.) ­— also backed Gorsuch and will face enormous pressure to do so again given their reelection races in states easily won by Trump in the last presidential election.

All five swing senators met with Trump at the White House Thursday in a sign of the heavy lobbying to come.

But progressive groups are hopeful that what they describe as a “multimillion-dollar” campaign on lawmakers across the country will galvanize an activated base and show senators that there would be severe political consequences for siding with Trump.

“This will be a 50-state campaign. Our members are fired up, our phones are ringing off the hook, and we are ready to fight this fight,” NARAL Pro-Choice America President Ilyse Hogue said in a Thursday conference call with reporters.

NARAL and other groups have provided no details on their specific plans, but have made it clear that they see the court fight as being a decisive battle over abortion rights.

Kennedy in a 1992 decision upheld Roe v. Wade, and his exit from the court could lead to a majority of five conservative justices opposed to abortion rights.

Hogue said the effort by groups including NARAL, Planned Parenthood, Indivisible and the National Women’s Law Center will marry a significant ad budget with heavy grass-roots organizing around the country.

There will be direct appeals to Murkowski and Collins to not vote to confirm a justice who would overturn Roe v. Wade.

Other Republicans will also hear from the left wing.

Hogue specifically called out Sen. Dean Heller Dean Arthur HellerOn The Trail: Democrats plan to hammer Trump on Social Security, Medicare Lobbying World Democrats spend big to put Senate in play MORE (R-Nev.), who is seen as the most vulnerable Senate Republican up for reelection this year. Heller is the only Senate Republican running in a state won by Hillary Clinton Hillary Diane Rodham ClintonDemocratic groups using Bloomberg money to launch M in Spanish language ads in Florida The Hill's Campaign Report: Presidential polls tighten weeks out from Election Day More than 50 Latino faith leaders endorse Biden MORE in 2016.

Republicans believe the court fight will help their side in the midterm elections by firing up grass-roots conservatives.

Conservative groups are already spending heavily on their own pressure campaign, and argue that red-state Democratic senators will pay for opposing a Trump nominee.

If liberals can’t stop the GOP Senate from confirming a Trump pick, they at least hope to use the issue to drive voters to the polls this November, when Democrats believe they can win back the House majority and possibly the Senate.

Leaders of groups backing the effort are quick to highlight the success Democratic women have had in races around the country, a point underlined by this week’s upset victory in New York by Alexandria Ocasio-Cortez over Rep. Joseph Crowley (N.Y.) in a Democratic primary.

“We are having this vacancy in the summer when everyone is calling the year of the women — where women are rising, where they are raising their voices,” said Fatima Goss-Graves, CEO and president of the National Women’s Law Center.

“They aren’t confused about the threat that is in front of them.”