Barack H. Obama has asked a question that has been on the minds of political observers/junkies ever since the election of Donald J. Trump as president of the United States.

“What happened to the Republican Party?” Obama has inquired.

What, indeed, has become of the Party of Lincoln, the Party of Ike, the Party of Reagan? Is has become the Party of Trump. Why is this a critical question? Because the current president brought no ideological mooring to the office to which he was elected.

The former president didn’t say it in so many words during his re-entry into the political debate this week, so I’ll say it here. The GOP has fallen victim to the cult of personality that Trump embodies.

Indeed, we have gotten a peek into that cult through the soon to be published book “Fear” written by veteran journalist Bob Woodward and by that anonymous essay published the other day by the New York Times.

Woodward and the mystery essayist both contend that Trump doesn’t adhere to any form of “conventional” Republican orthodoxy.

Moreover, as Obama said in Illinois, Republicans ought to be aghast that the president is making nice with the former head of the KGB, given that Republicans’ signature foreign policy issue for decades — during the Dwight Eisenhower years — was to oppose communism, led by the former Soviet Union.

Republicans during the Ronald Reagan era would rail against the annual budget deficit. On Trump’s watch, we’re watching the deficit escalate, yet GOP members of Congress give the president a pass.

The Party of Lincoln never would give moral equivalence to Nazis and Klansmen to the people who opposed them at the Charlottesville, Va., riot in 2017.

Yes, the question posed by the 44th president of the United States is a valid one.

What has happened to the Republican Party?