If a party could declare moral bankruptcy, today’s Republican Party would be in Chapter 11.

This party needs to just shut itself down and start over — now. Seriously, someone please start a New Republican Party!

America needs a healthy two-party system. America needs a healthy center-right party to ensure that the Democrats remain a healthy center-left party. America needs a center-right party ready to offer market-based solutions to issues like climate change. America needs a center-right party that will support common-sense gun laws. America needs a center-right party that will support common-sense fiscal policy. America needs a center-right party to support both free trade and aid to workers impacted by it. America needs a center-right party that appreciates how much more complicated foreign policy is today, when you have to manage weak and collapsing nations, not just muscle strong ones.

But this Republican Party is none of those things. Today’s G.O.P. is to governing what Trump University is to education — an ethically challenged enterprise that enriches and perpetuates itself by shedding all pretense of standing for real principles, or a truly relevant value proposition, and instead plays on the ignorance and fears of the public.

It is just an empty shell, selling pieces of itself to the highest bidders, — policy by policy — a little to the Tea Party over here, a little to Big Oil over there, a little to the gun lobby, to antitax zealots, to climate-change deniers. And before you know it, the party stands for an incoherent mess of ideas unrelated to any theory of where the world is going or how America actually becomes great again in the 21st century.

It becomes instead a coalition of men and women who sell pieces of their brand to whoever can most energize their base in order for them to get re-elected in order for them to sell more pieces of their brand in order to get re-elected.

And we know just how little they are attached to any principles, because today’s Republican Party’s elders have told us so by (with a few notable exceptions) being so willing to throw their support behind a presidential candidate who they know is utterly ignorant of policy, has done no homework, has engaged in racist attacks on a sitting judge, has mocked a disabled reporter, has impugned an entire religious community, and has tossed off ignorant proposals for walls, for letting allies go it alone and go nuclear and for overturning trade treaties, rules of war and nuclear agreements in ways that would be wildly destabilizing if he took office.

Despite that, all top G.O.P. leaders say they will still support Donald Trump — even if he’s dabbled in a “textbook definition” of racism, as House Speaker Paul Ryan described it — because he will sign off on their agenda and can do only limited damage given our checks and balances.

Really? Mr. Speaker, your agenda is a mess, Trump will pay even less attention to you if he is president and, as Senator Lindsey Graham rightly put it, there has to be a time “when the love of country will trump hatred of Hillary.”

Will it ever be that time with this version of the G.O.P.?

Et tu, John McCain? You didn’t break under torture from the North Vietnamese, but your hunger for re-election is so great that you don’t dare raise your voice against Trump? I hope you lose. You deserve to. Marco Rubio? You called Trump “a con man,” he insults your very being and you still endorse him? Good riddance.

Chris Christie, have you not an ounce of self-respect? You’re serving as the valet to a man who claimed, falsely, that on 9/11, in Jersey City, home to many Arab-Americans, “thousands and thousands of people were cheering as that building was coming down.” Christie is backing a man who made up a baldfaced lie about residents of his own state so that maybe he can be his vice president. Contemptible.

This is exactly why so many Republican voters opted for Trump in the first place. They intuited that the only thing these G.O.P. politicians were interested in was holding onto their seats in office — and they were right. It made voters so utterly cynical that many figured, Why not inflict Trump on them? It’s all just a con game anyway. And at least Trump sticks it to all of those politically correct liberals. And anyway, governing doesn’t matter — only attitude.

And who taught them that?

But it does matter. I know so many thoughtful conservatives who know it matters. One of them has got to start the N.R.P. — New Republican Party — a center-right party liberated from all the Trump birthers, the Sarah Palins, the Grover Norquists, the Sean Hannitys, the Rush Limbaughs, the gun lobby, the oil lobby and every other narrow-interest group, a party that redefines a principled conservatism. Raise your money for it on the internet. If Bernie Sanders can, you can.

This is such a pivotal moment; the world we shaped after W.W. II is going wobbly. This is a time for America to be at its best, defending its best values, which are now under assault in so many places — pluralism, immigration, democracy, trade, the rule of law and the virtue of open societies. Trump will never be a credible messenger, or a messenger at all, for those values. A New Republican Party can be.

If you build it, they will come.