WASHINGTON — There are few prizes in Washington bigger than a Supreme Court vacancy. With only four months to go before the midterm elections, and control of the Senate hanging by a two-vote margin, the stakes just got higher as Sen. Ted Cruz seeks to fend off Democratic Rep. Beto O'Rourke.

The incumbent and his challenger don't agree on much. But they do agree on that.

"After today, this race to represent Texas in the Senate matters more than ever," O'Rourke tweeted late Wednesday. On Thursday morning, Cruz chimed in with his concurrence.

Fully agree. And the overwhelming majority of Texans want Supreme Court Justices who will preserve the Constitution & Bill of Rights, not undermine our rights and legislate from the bench. https://t.co/D5zVNThUfq — Ted Cruz (@tedcruz) June 28, 2018

"Fully agree," the senator tweeted. "And the overwhelming majority of Texans want Supreme Court Justices who will preserve the Constitution & Bill of Rights, not undermine our rights and legislate from the bench."

News of Justice Anthony Kennedy's retirement sent a thrill through conservative ranks Wednesday afternoon. Over his 30 plus years on the high court, the President Ronald Reagan appointee had emerged as a centrist and, especially in the last decade, the controlling swing vote on a host of contentious and momentous issues, including affirmative action, abortion rights and same sex marriage.

The other eight members of the court are evenly divided between conservatives and liberals, which means that President Donald Trump has the opportunity to steer the court to the right for a generation.

"We have to pick a great one. We have to pick one that's going to be there for 40 years, 45 years," Trump told a rally at a hockey arena in Fargo, N.D. on Wednesday night.

Cruz made much the same point earlier in the day, telling Fox News that this vacancy "is an opportunity to really have a profound impact on the court, an impact on the court that could last for decades."

For Cruz, the vacancy is a welcome turn of events.

Democrats shudder at the prospect of a court without Kennedy, where instead of a 5-4 majority with a centrist serving as a check on the conservative wing, another Trump pick shifts the balance of power and creates a majority willing to go much further than Kennedy was on voting rights, race-based preferences in college admissions and reproductive rights.

"Everything we care about is on the line," O'Rourke told supporters in a fundraising blast.

Rep. Beto O'Rourke of El Paso, right, is challenging Sen. Ted Cruz in 2018. (Rose Baca & Ashley Landis/The Dallas Morning News)

Timing of the confirmation process quickly emerged as a huge point of contention.

O'Rourke hasn't said directly whether he agrees with Senate Democrats demanding a delay until after the November elections. But his email blast suggested that he does: "Each of us has to do everything we can to make sure Beto is in the Senate when the next confirmation vote is called."

In the last week alone, the Supreme Court has issued close rulings on the president's Muslim ban, on workers’ rights, on voting rights, on gerrymandering, and on a woman’s right to choose. The stakes for this nomination couldn't be higher. We have to get this right. — Beto O'Rourke (@BetoORourke) June 27, 2018

Don Willett, a former Texas Supreme Court justice named by Trump to a federal appeals court and confirmed to that post in December, is on the president's list of 25 finalists for the next Supreme Court vacancy. During the 2016 campaign, Trump crafted the list with input from the Federalist Society, a conservative legal group, to reassure conservatives that electing him — despite the qualms many felt about his character and inconsistency on key issues — would be worth it.

He updated the list last November and affirmed on Wednesday that he'll choose the next nominee from that list.

Cruz supports the the only non-judge on Trump's list, Utah Sen. Mike Lee, a close ally and, like himself, a former Supreme Court law clerk. Lee clerked for Justice Samuel Alito. Cruz clerked for the late Chief Justice William Rehnquist.

Sen. John Cornyn said that he's not familiar with everyone on Trump's list but "the ones I do know look to be very high caliber."

Asked if he has a favorite among the options, he told Texas journalists on a weekly call, "I do not."

Both Texans serve on the Judiciary Committee.

Republicans refused to hold a hearing on President Barack Obama's nominee to replace Justice Antonin Scalia after the conservative stalwart died suddenly in February 2016, insisting that the seat should remain vacant until voters chose a new president that November, nearly nine months later — an unprecedented move.

Cruz was an early advocate of that tactic but now argues there's no reason to delay until after the midterm elections this November, four months from now. He and other Republicans say a midterm election is fundamentally different from a presidential election.

Cornyn, the No. 2 Senate Republican, argued Thursday that Democrats themselves had set the precedent for avoiding a confirmation during a presidential election year. He recalled that Obama's own vice president, Joe Biden, had made the case for such a delay — in 1992, when he chaired the Senate Judiciary Committee.

He noted that in 2010, another midterm year, Democrats controlled the Senate and were perfectly happy to confirm an Obama nominee, Elena Kagan, to the high court.

It's one thing to delay a confirmation "during the heat of the presidential campaign season," Cornyn said. But he added, "That doesn't translate for a midterm election, obviously, because we're going to have the same president after."