There's a potential nightmare for Hillary Clinton if she wins the presidency but Republicans hold onto control of the Senate — a blockade of her Supreme Court picks.

That prospect — which could impact every aspect of American life including climate regulations, abortion and gun rights — was first raised by Sen. John McCain of Arizona, then Ted Cruz of Texas and now Richard Burr of North Carolina, who CNN reported Monday talked up the idea at a private event over the weekend.

"If Hillary Clinton becomes president, I am going to do everything I can do to make sure four years from now, we still got an opening on the Supreme Court," Burr, chairman of the Senate Intelligence Committee, told a group of Republican volunteers, according to CNN.

Senate Republican leader Mitch McConnell, R-Ky., hasn't publicly endorsed Burr's strategy, which is aimed at denying a lasting, liberal majority on the court, but he hasn't disavowed it either. There are now eight justices, four nominated by Democratic presidents and four by Republicans, after the death of Antonin Scalia in February.

Democrats could circumvent a GOP blockade if they control the Senate by changing the chamber's rules, even though that would be a controversial move. But a Republican-held Senate could deny Clinton the 60-vote margin needed to advance high-court picks on the floor.

Control of the Senate is on a knife edge in the polls, with a half-dozen races considered tossups and the latest revelations about the FBI reviewing additional Clinton e-mails adding even more uncertainty in the final week.

The next president could have an unusual opportunity to shape the future of the high court for years to come. Several justices will be on retirement watch over the next four years. Ruth Bader Ginsburg is 83, Anthony Kennedy is 80 and Stephen Breyer is 78.

Should Clinton fill Scalia's seat, the court would have a majority of Democratic appointees for the first time since 1969, at the end of the liberal era under Chief Justice Earl Warren. Conversely, a President Donald Trump could help secure a conservative majority on the court for a generation.

There's no constitutional requirement that the Senate confirm anyone. But blocking nominees for an entire presidential term would be unprecedented. The longest Supreme Court vacancy lasted 835 days in the 1840s, according to the Congressional Research Service.

McConnell has repeatedly declared that Merrick Garland, President Obama's pick, won't get a vote in this Congress. But he hasn't explicitly guaranteed the next president's nominee will.

"The leader has been clear that it will be the next president who makes the nomination for the Scalia vacancy," said McConnell spokesman Don Stewart, who declined to comment further.

But voters aren't just choosing a president next Tuesday; they're also choosing the body that gets to approve, or block, nominees.

Indeed, other Republicans — even those who aren't supporting Trump, like Rep. Joe Heck, who is running in Nevada for a Senate seat, or Sen. Pat Toomey in Pennsylvania — have been using the Supreme Court to court conservative voters, although they at least say they would consider Clinton's picks.