President Trump might not have won the Nov. 8 election had he not published a list of conservative judges from which he promised to pick his nominee to the Supreme Court.

There is no sign that the president, who will make his nomination Tuesday evening, is having second thoughts. But if, for the sake of showmanship or anything else, he is tempted to make a surprise pick, he should suppress that feeling at all costs. The list is a talisman among conservative and Republican voters, and a test of the value of the president's word and his ideological seriousness. If he does not pick from the list it will cost him a permanent loss of support and gain him the enmity of people he needs over the next four years.

The single-most important factor prompting people to vote for Trump (27 percent in one NBC exit poll) was that he would make the right choice for the court. In conservative and especially social conservative circles, the court was the central reason they lined up behind Trump, who lacked bonafides as an opponent of abortion.

His reluctant conservative backers essentially thought this: Trump isn't one of us, but he, unlike Hillary, will put a few of us on the Supreme Court. Those conservatives who rejected that line of thought and stayed in the #NeverTrump camp were, often, those who argued that he could not be trusted to stick to his list. At one point early in his run, Trump even named his sister, liberal judge Elizabeth Trump Grau, as a potential nominee.

That's why the list of 21 judges was a masterstroke in the campaign, dangling a yearned-for outcome before the eyes of doubters and prompted them to set aside their skepticism and pull the lever for the GOP nominee. Conservative voters who distrusted Trump for his big spending, his character, and his demeanor, swallowed hard and backed him to save the courts.

Without new conservatives on the high court, Hobby Lobby could be overturned, smashing conscience protections for anyone who deviates from the moral code of the secular elite. Without new conservatives on the Supreme Court, liberals could gut Heller, blasting a hole in the Second Amendment. The First Amendment wouldn't be safe. Roe v. Wade would be preserved and expanded.

Those dangers are reason to harbor concerns right up until the moment that a good nominee is named. But are there more specific reasons for worry?

One is that Trump is a showman, and he likes surprises. He has also shown himself to be persuadable. Whilst he has shown himself resilient in the face of a barrage of attacks over his immigration executive order, he is also a deal maker. There must be a slight temptation to pick a Supreme Court justice who would be a pleasant surprise to Democrats rather than stoking their outrage. Trump is probably made of sterner stuff; we certainly hope so.

Democrats are making noises that they will filibuster any GOP nominee. They want revenge for Republicans' blocking President Obama's nomination of Merrick Garland. But that's just the latest justification for a policy of filibustering GOP nominees that has been standard Democratic practice since President Clinton left office.

Sen. Chuck Schumer, D-N.Y., now minority leader, spearheaded the Democrats' push in the Bush years to expand filibusters of lower-court nominees. All of the most prominent Democrats, including Schumer, and then-senators Barack Obama, Hillary Clinton, Harry Reid, and John Kerry, voted to filibuster Sam Alito.

Nothing will unify the right better than a fight against hypocritical obstructionist Democrats with abortion, religious liberty, free speech, and the Second Amendment at stake.

Donald Trump has had political success by being unpredictable. Now is not the time, and the Supreme Court is not the issue, to give the country any more surprises.