A legion of Donald Trump's Republican critics have finally decided to speak up, but it has probably taken too long for them to put the front-runner in their cross hairs.

These edgy rebukes have come in quick succession since Super Tuesday, from Mitt Romney and John McCain, from congressional leaders, and from two of his three opponents for the nomination.

The loudest blast came from 104 national security "experts," who called Trump "fundamentally dishonest" in an open letter, and who vow to "work energetically to prevent the election of someone so utterly unfitted to the office."

Maybe you welcome these voices of dissent, but it's worth exploring what these Republican stalwarts are criticizing exactly, because they don't tell the whole truth.

No doubt, it's easy to see that Trump's platform fluctuates between fatuous and terrifying, and it's not hard to spot a bigot and narcissist, especially when he is so proud of it.

But there is an emerging perception that Trump has inspired more GOP vitriol of late because he is Not Their Kind, in ways that matter most to the party he aspires to hijack.

For starters, he is self-funded, which means he will not bow to power brokers, some special interests, or Rovian Svengalis. He is arrogant enough to tell the leeches of K-Street to get lost, which threatens the political wellspring. He is hostile to existing trade deals, which is an assault on corporate dominion.

He consistently trashes the purveyors of perpetual war, notably the Neocons, with gems such as "We would have been better off if the politicians took a day off instead of going into war." He takes a wrecking ball to the myth of Iraq - right down to reminding debate audiences that the last GOP president "lied us into war." They booed.

True, Trump isn't usually so astute, and he is a clear and present danger to everybody. Mitch McConnell has even instructed senators seeking re-election that they could run negative ads about Trump, on the hope of creating political distance.

But the only thing Republicans can do is accuse him of not being "a true conservative." It's as if he dances on the grave of Ronald Reagan, whose dim-bulb mantra - Thou Shalt Not Criticize a Fellow Republican - is the rotting heirloom of party fealty and its primacy over progress and country.

An extraordinary example of this occurred during Thursday night's debate, when Marco Rubio praised Michigan governor Rick Snyder's handling of the Flint water catastrophe.

Essentially, Rubio thought it was commendable that the Republican administration's poisoning of thousands of children wasn't deliberate.

It was a reminder that in Trump's party, criticism has no validity unless the target wears a "D." But the rules are changing at high volume, because the campaign has been dominated by a runaway id.

He bashes Republicans, often when he has nothing to say. And they return the volley, because he threatens what they value. It hardly matters that he seems too dense to debate policy. That is almost Republican doctrine: This is the party that gave us science denial. The party that sneers at education. The party that promotes its candidates as a preferred beer-drinking partner.

This nurturing of deep thinkers and statesmen has produced a frontrunner who talks about his private parts on the debate stage.

Now the GOP is stuck with him. Among the few who accept this fate is Gov. Chris Christie (R-Hostage), who stands with David Duke and Jeff Sessions and Sarah Palin and endorses a candidate who has no discernible position on anything besides inciting racial hatred.

They know something the mainstream disciples of St. Gipper probably know, but won't admit: It's Trump's party, and only the voters will be able to stop him at this point. To put this in perspective, weep uncontrollably.

More: Recent Star-Ledger editorials.

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