Transcript for Trump says he'll choose justice from list of 25 he's been compiling

next justice, which could shift the balance on the court for more than a generation. President trump saying he will pick someone to place justice Kennedy. And so, Terry tonight on the future of the court, and on Democrats scrambling, but with few options tonight. Reporter: President trump on the brink of reshaping the supreme court for generations with his choice to replace justice Anthony Kennedy. We have to pick one that's going to be there for 40 years, 45 years. Reporter: The president says he'll choose from a list of 25 candidates he began compiling in 2016. High on the short list, judge Thomas hardima of Pittsburgh, 52. A strong gun rights supporters, he was said to be runner-up last year when trump picked Neil Gorsuch. Judge Brett Kavanaugh of Washington D.C., also 52, and like Gorsuch, also a former clerk to justice Kennedy. He worked in the George W. Bush white house. And judge Amy coney Barrett of Chicago, 46, a former clerk to the late justice Antonin Scalia. She's criticized roe versus wade and is a mom of seven children, including a special needs child and two children adopted from Haiti. Democrats, outnumbered, are already trying to stop any vote, echoing the argument Republicans used when they blocked president Obama's nominee, Merrick Garland, in an election year. Senator Tammy Duckworth of Illinois tweeting, "The American people should have a voice in the selection of their next supreme court justice." But there's a big difference. Republicans had the votes to block Garland. Democrats are in the minority now. We will vote to confirm justice Kennedy's successor this fall. Reporter: But for every senator, this will be a monumental vote. Perhaps the biggest issue, the right to choose abortion. President trump in 2016 became the first Republican nominee to explicitly promise the end of roe versus wade. Well, if we put another two or perhaps three justices on, that's really what's going to be -- that will happen. And that will happen automatically, in my opinion, because I am putting pro-life justices on the court. Reporter: Now, with trump ready to deliver, there's tremendous pressure on the two pro-choice Republican women senators, Lisa murkowski of Alaska and Maine's Susan Collins. Roe V wade is an important precedent and it is settled law. Reporter: If Democrats have any chance of blocking a nomination, they can't afford to lose a single vote, but now three Democrats up for re-election in states trump won are feeling the heat. They all voted to confirm Neil Gorsuch, but that didn't stop the president from attacking one of them, north Dakota's Heidi Heitkamp, in her own backyard last night. Heidi will vote no to any pick we make for the supreme court. So, let's bring back in Terry Moran from the white house. And Terry, with the president's second nomination to the court now, less than two years into his presidency, this court will likely soon lean solidly conservative, and the president's potential picks, they're all relatively young. Reporter: That's right, David. That long list of 25, the average age is somewhere just over 50 years old. When the president says his choice will have an impact on America lasting for decades, he's absolutely right. And that sharp shift to the right that this nomination will represent, if confirmed, that will operate as a kind of invitation to conservative lawmakers and activists around the country who will bring cases that target roe versus wade and affirmative action and other conservative causes. In a way, this court, later this year, will be open for business for conservatives. David? Terry Moran at the white house. Terry, thank you.

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