Transcript for Stakes high in battle to replace Kennedy on Supreme Court

As we've said the Kennedy retirement has set the stage for a titanic fight over the future of the supreme court and president trump promised to make his pick from a list of conservative judges and trying to delay and Jon Karl is tracking it. Good morning. Reporter: Good morning. For many conservatives, Donald Trump's promise to transform the supreme court was the single most important reason they came to support him. Now he has a chance to make good on that promise but he will first face an epic confirmation battle. Overnight in Fargo, north Dakota, president trump turned his next supreme court pick into a campaign rallying cry. Justice Kennedy's retirement makes the issue of senate control one of the vital issues of our time. The most important thing we can do. Reporter: With midterm elections on the horizon, the president called on Republicans to act quickly. We have to pick one that's going to be there for 40 years, 45 years. We need intellect, we need so many things. Reporter: He slammed those who would get in his way. Democrats want judges who will rewrite the constitution any way they want to do it and take away your second amendment, erase your borders, throw open the jailhouse doors and destroy your freedoms. Reporter: The president's choice could be the most consequential supreme court nomination in a half century. Replacing the swing vote on the court and likely shifting the balance of power decisively in favor of the conservatives. Leonard Leo is the conservative legal expert who will help the president make his pick. It's a transformative opportunity for the president and the country. Reporter: To transform the supreme court. Well, to transform the rule of law. Reporter: During the campaign he promised to pick only pro-life judges. I am putting pro-life justices on the court. Reporter: Anti-abortion activists are calling it a pivotal moment while abortion rights defenders are saying they are in dire immediate danger. The senate should reject on a bipartisan basis any justice who would overturn roe V. Wade or undermeineke health care protections. Reporter: Democrats insist there should be no confirmation vote at all until after the midterm elections and point to the fact that Republicans blocked Barack Obama's last pick for ten months until the 2016 presidential election but Republican leader Mitch Mcconnell says there must be no delay. We will vote to confirm justice Kennedy's successor this fall. Reporter: Republicans are dealing with a razor thin one-vote majority in the senate. That means they can afford to lose only one and when you consider the fact that John McCain hasn't been in the senate's vote since late last year there is no margin of error and the president says we lose one if someone gets a bad cold. That's why, George, you can expect Republicans to put intense pressure on three Democrats, three Democrats who voted for Neil Gorsuch, his choice last time around and who are now this year up for re-election in states trump won big. Republicans are trying to put pressure on those Democrats. Democrats trying to put pressure on two key Republican senator, Susan Collins of Maine, Lisa murkowski of Alaska. Reporter: Absolutely. They are both in favor of abortion rights but both also did support Neil Gorsuch last time around and Republicans will be putting a lot of pressure on their own, those two to support the president's nominee this time, as well. Jon, thanks very much.

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