President Trump has done everything to hype his imminent Supreme Court nominee except cut a 15-second spot demanding that Americans tune in at 9 p.m. Eastern, 8 Central on Monday night. Setting a prime-time announcement is, by now, expected from Trump, who on Monday morning tweeted that his announcement reflected “the most important decision a U.S. President can make.” He didn’t explicitly ask Americans to “tune in” — but he’s done it before, most recently for a rally in West Virginia last August.

There’s a grain of truth to Trump’s sales pitch, of course. A Supreme Court nomination is, indeed, one of the most significant decisions a president can make, shaping the judiciary of the country for years to follow. And it makes sense that Trump would want America to hear his pitch for his nominee at the outset: That person may face one of the toughest nomination fights in decades.

It used to be the case that nominees to the court were often approved with a voice vote. Franklin Roosevelt had nine justices confirmed as president; seven of them didn’t even need more than a generic thumbs-up from the Democratic-controlled Senate.

Since Lyndon Johnson, the going has been a bit rougher. He had one nominee confirmed by voice vote in 1965. It hasn’t happened since.

Which isn’t to say that all of the nominees since have seen significant fights. Since the presidency of Gerald Ford, only seven of 15 nominees for the court have received more than 30 votes in opposition. However, that includes the four most recent confirmed justices.

Why? In large part because members of the opposing party have been less willing to support presidents’ nominees. Since the confirmation of John G. Roberts Jr. to serve as chief justice, no nominee has received more than a quarter of supportive votes from the party that didn’t control the White House.

There are some interesting details in the charts above that are worth noting in the context of Trump’s new nominee.

Consider, for example, the nominations of Robert Bork and Clarence Thomas. Both were hotly contested, with Bork being rejected 42-58 and Thomas being confirmed 52-48. The composition of the Senate was about the same for each nomination, with Democrats having a 10-seat advantage for Bork and a 14-vote advantage for Thomas. [This article uses party caucuses as a measure, meaning, for example, that Sen. Bernie Sanders (I-Vt.) is added to the Democrats in these calculations.] But Bork received only about 4 percent of the vote from Democrats, while 89 percent of Republicans backed him. For Thomas, both of those numbers were larger: 95 percent of Republicans and 19 percent of Democrats supported him. That made the difference.

The nomination of Neil M. Gorsuch last year saw the biggest split between members of the president’s party and members of the opposition. Nearly every Republican and almost no Democrat backed him, yielding a 92-percentage-point difference between the two caucuses. Since Gorsuch couldn’t get enough support from Democrats to avoid a filibuster, Senate Majority Leader Mitch McConnell (R-Ky.) pushed a rules change to keep Supreme Court nominees from being able to be filibustered.

Ford, Ronald Reagan and George H.W. Bush all advanced nominees with the Senate controlled by the opposition, mandating that they make the case to the Democratic majority for their nominees. (The pitch for Bork was unsuccessful.) Those three presidents were also operating in an environment in which there was broad leeway given to a president’s nominees, something that has eroded in recent years — contributing to the reduced willingness of the opposition party to support a president’s nominee.

Trump’s next pick faces a Senate in which the president’s party has its narrowest majority of any confirmation fight since Ford. The Gorsuch fight was a tough fight because the Republican majority was so narrow, with a four-vote Republican advantage. With the election of Sen. Doug Jones (D-Ala.) last year, that majority is now only two votes. The illness of Sen. John McCain (R-Ariz.) makes the margin even narrower: If he can’t vote, Republicans have only one vote to spare from their own caucus.

The wild card here is how much support Trump’s nominee gets from Democrats. Since Ford, there have been no Supreme Court nominees who didn’t receive at least some support from the opposition. Bork’s two Democratic-caucus votes are the lowest that have been recorded from the opposition over that period. If the Democratic caucus holds together, the fight could come down to the vagaries of one or two Republicans — as have so many recent fights on Capitol Hill.

Trump seems disinclined to make any overtures to Senate Democrats, instead relying on the opposing party’s need to hold a number of red-state seats in the midterm elections. He will probably rely on his ability to target those red-state Democrats as leverage for the votes he needs — a much different strategy than nominating someone who some Democrats might otherwise find tolerable.

It’s the sort of pressure red-state Democrats faced in 2013 when pushed to back new regulations on gun purchases in the wake of the mass shooting in Newtown, Conn. Several Democrats from Republican states joined the Republican caucus in filibustering that effort and the regulations were blocked.

Only one, Sen. Heidi Heitkamp (D-N.D.) is still in the Senate. She’s up for reelection this year.