The decision to announce his Supreme Court nominee in prime time was Trump's idea, an aide said, in an attempt to draw a larger audience Tuesday evening than he would receive during the day.

It is modeled after President George W. Bush's introduction of Chief Justice John Roberts in an evening appearance in the East Room of the White House.

After the death of late Justice Antonin Scalia, President Barack Obama nominated Merrick Garland, but the Republican majority prevented his confirmation. This move maintained the vacancy on the court -- leaving a space open for Trump to make his pick.

Scalia was a right-leaning voice on the court, and Trump's pick is expected to fil

l his place. Trump said in an interview with "60 Minutes" after he was elected that although he thought the issue of same-sex marriage was "settled," he planned to appoint anti-abortion rights justices.

There are three major candidates whose names have been mentioned most often: Thomas Hardiman, currently a judge on the 3rd Circuit; William Pryor, who sits on the 11th Circuit and is a former Alabama attorney general; and 10th Circuit judge Neil Gorsuch of Colorado.  All are under the age of 55 and, to varying degrees, would be acceptable to most conservatives.

But Donald Trump loves to surprise people, so he may not choose a nominee from among these three.  As a surprise pick, some pundits are suggesting he nominate Senator Ted Cruz.  Senator Cruz still wants to be president, so it is unlikely he would accept a nomination to the high court.

But with Trump, you never know.