My first thought was that they won't even try. They'll use the open seat as a political issue — an argument why it is so important to reelect Trump and to keep a GOP majority in the Senate. And the backup plan can be that if Trump loses, they can accomplish the appointment after the election, before the new Senate and President are sworn in. So what if they said something else before the election?!
But then — in discussion here at Meadhouse — the thought came up that this election could be contested. There's so much talk about election fraud and mail-in voting, that there could be
Bush v. Gore type litigation arising in various states, and the outcome of the election could well depend on that. Right now, the Supreme Court has only 8 Justices, and though there are presently 5 conservatives and only 3 liberals, a 4-4 tie is possible, with one vote switch, and Trump might want his person on the Court to lock in a conservative majority.
ADDED: The strongest argument for Trump to go right ahead and immediately nominate someone is that President Obama made a nomination in the election year of 2016 when Antonin Scalia died. Obama's nominee was not confirmed, but that was because the GOP controlled the Senate. There was nothing about Obama's
lack of support in the Senate that made him more willing to put forward a nomination in an election year. He made the nomination
in spite of the lack of support. Why should Trump refrain when he has Senate support?
AND:
"McConnell says Senate will move to confirm Ginsburg replacement" (WaPo).
“President Trump’s nominee will receive a vote on the floor of the United States Senate," McConnell said in a statement hours after the court announced Ginsburg’s death.
Also at that link: "More than 90 minutes after news of Ginsburg’s death broke, President Trump — speaking at a campaign rally in Bemidji, Minn. — seemingly remained unaware of the news.
While closing out the rally, however, Trump alluded to the importance of the Supreme Court’s direction in the upcoming election. 'We will nominate judges and justices who interpret the Constitution as written,' Trump told the crowd, to cheers and shouts. He told his supporters that the next president 'will have anywhere from one to four' vacancies on the Supreme Court to fill. 'Think of that,' Trump said, warning that conservatives would be 'stuck' for decades with a Supreme Court they did not like if the Democrats won in the fall."
And (same link): "Days before she died, Ginsburg told her granddaughter that she felt strongly that her Supreme Court seat not be filled until after the presidential election, according to NPR. 'My most fervent wish is that I will not be replaced until a new president is installed,' she dictated in a statement to her granddaughter, Clara Spera."
Joe Biden ought to come right out and say who he will nominate if he is elected.