There is no way to deny it now: Donald Trump is the frontrunner for the Republican nomination for President of the United States. Remarkably, he has shown that his appeal is not short-lived, limited to only about 33% of the GOP voters, or narrow among one class or region. Indeed, his victories in New Hampshire, South Carolina, and Nevada display a broad appeal to a wide swath of voters and - contrary to those, including myself, who have said he might not perform as well if he had only one opponent - and his support could even grow larger.

Trump has also shown that the marriage of celebrity culture and presidential-nominating media-circus atmosphere has been consummated. Perhaps it will never be the same. In the past fifty years we have gone from "Kennedy-esque", to a professional actor, to "very cool and hip". The Trump phenomenon in this Age of Kardashian was the logical next phase. (But I don't want to even think of the next one - Folies Bergere?)

To date, Trump has perfectly blended his slick image of the card sharp winner, the ultimate dealmaker, and his reflexive thermonuclear responses to any criticism into the movie hero that we all love - he is the secret agent who never loses, the Rambo who shoots everyone down, and the simple good guy - bad guy worldview that is easy to understand. To this he has added a populist message that represents some of the worst elements of American (and European) populism - i.e. racism, scapegoating, drastic and uncompromising solutions, and ridicule of those who stand in his way. He is not just giving voice to a real anger that is very much alive; he is promising to punish those who have caused the anger.

There are some - maybe more than a few - that are still waiting. Those who believe that this has all been a game, a vanity campaign that folks took too seriously and even surprised Trump himself. In that scenario, he caught on beyond even his own wildest fantasies and now has had to play out the role. And there are those who still feel that Trump does not believe a word of what he is saying. He is really a successful businessman who has worked with Latinos, Muslims and Arabs, women executive - he cannot really believe the things he is saying. That is only the shtick that got him here.

But then there are now the millions - and growing - of Americans who tell us things like "I like him because no one owns him" or "Sometimes he gets out of hand but he has a lot of good ideas". So this is the best time to ask: Just what are those "good ideas"? Is he really going to go door-to-door, disrupt families and deport 12 million "illegals"? Is he serious about building a wall and having Mexico pay for it? Has he talked to President Enrique Pena Nieto about this and secured the promise that Mexico will discuss this? Is he serious that no Muslims will enter the United States? So let's say that diplomats can arrive and businesspeople who have to make "deals", what is the cut off for who can come and who cannot? How much will this monitoring cost?

Speaking of costs, Trump has promised over 11 trillion dollars in tax cuts over the next few years but has also promised to not touch Social Security or Medicare. He has not come up with anywhere near that much in cuts in spending - yet he rails against the $19 trillion debt the US finds itself in. He will fight ISIS and bring them to its knees? Yet he has been clear that intervention in Libya was a mistake and that the Iraq War was a disaster. How will he destroy ISIS? How much will it cost? Where will the money come from? How will he mend fences with Muslims he has already alienated?

After Nevada, Trump could still get a serious challenge from Marco Rubio in a one-on-one race. But it really doesn't seem likely. In Nevada, Trump hit 46% of GOP caucus voters. That is pretty daunting for any challenger. The frontrunner has proven his critics, his opponents, his observers, and even himself to be very good at playing this game. Now he owes us some answers.