Donald Trump has one great advantage over all the other presidential candidates:  he has no set of core beliefs.  He reminds me of that old Groucho Marx line, "Those are my principles, and if you don't like them… well, I have others."

He's the current frontrunner in a close race with Ted Cruz with the rest of the field training far behind.  The GOP establishment wishes both would go away, but they're warming to Trump because they think he'd have a better chance of winning in November and can't stomach Cruz.

Trump is a shameless shape shifter, and that makes him very flexible and very dangerous, especially for voters just looking for "change" but not knowing what they want or what they're voting for until it's too late.

He can do it easily because, as he has shown, he really believes in nothing but himself. He's made 180-degree turns while adamantly denying he's changed anything.

If he gets the nomination, he won't be a traditional candidate and won't play by any rules but his own, and that worries the party poobahs, who can't count on his loyalty and fear he could go down in flames, taking their House and Senate majorities with him.

He has tapped into a dissatisfaction and rage among primarily less-educated white voters fed up with the establishment while offending brown and black voters with his racist and xenophobic rants.

Trump has been trying to out-conservative Ted Cruz with evangelicals, toting his Bible to some events, albeit fumbling his references.  If he's the nominee, he'll leave it at home and start introducing his Orthodox Jewish daughter to show how inclusive he is.

The anti-immigration card has worked well for him so far, tapping a surprisingly large reservoir of xenophobia in an anxious electorate, but staying on that track risks any chance of capturing the sizeable Hispanic and African-American vote to the Democrats.

He'll make the Israel trip he postponed last year and reiterate his vow to move the US Embassy to Jerusalem  — don't they all? – but "at the right time."  He'll repeat Mitt Romney's promise not to push Israel into peace talks, saying he'll wait until the Israelis and Palestinians call to say they're both ready.  And he'll try to parlay that into Bibi Netanyahu's endorsement. 

Assuming Hillary Clinton is the Democratic candidate, Trump, a three-times divorced admitted adulterer, will preach the sanctity of marriage while attacking Bill Clinton's philandering, which he'll blame on Hillary. Look for more snarky remarks about her bathroom habits.

Sarah Palin may be an asset when courting the GOP's lunatic fringe but she's a decided liability in the general election and will be sent back to Alaska, where she can keep an eye on Russia from her porch.

Trump says he will "get along very well" with Vladimir Putin, who has called Trump "bright and talented." He called Putin "highly respected" and he feels they'll "be able to work well with each other towards defeating terrorism and restoring world peace."

One thing won't change: His assault on media. It has worked well for him.  Very well.  He has played it like a virtuoso, garnering free media, setting the rules, controlling the news cycle with dramatic announcements and extreme rhetoric, phoning in his interviews and deflecting tough questions. He's good for ratings, so TV moguls will try to stay on his good side lest he bless the competition with his presence.

Something else won't change if Trump is the GOP nominee: He'll still be a thin-skinned, arrogant, narcissistic bullying liar, misogynist and hater with galactic ego.