Dan Janison Melville. N.Y. Tuesday January 26, 2010. Daniel Janison,

Dan Janison has been a reporter at Newsday since 1997.

The new “in” crowd instantly traded songbooks with the new “out” crowd.

Suddenly, some Democrats who applauded President Barack Obama’s expansion of executive powers to evade congressional blockades will express deep concern about how the White House fiats may exceed constitutional authority.

Suddenly, some Republicans who derided Democratic judicial appointees as ideologically biased will hail the nomination of Supreme Court judges assigned to overturn Roe v. Wade.

Suddenly, many anti-Donald Trump rally-goers will say their peaceful demonstrations should not be smeared in the public mind by, say, a subway attack on a man in a “Make America Great Again” cap.

As in: Our demonstrations are paragons of free expression!

Suddenly, many fans from the rowdier Trump rallies where counterprotesters were roughed up denounce anti-Trump demonstrations as planned agitation meant to cloud a legitimate election.

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As in: Our rallies were paragons of free expression!

All this could have been expected once Trump won.

Suddenly, the anti-establishment candidate who denounced the “rigging” of the Republican primaries by “insiders” against him finds Reince Priebus — party chairman since 2011 — to be the perfect candidate for chief of staff.

Suddenly, Hillary Clinton, whose supporters hailed FBI Director James Comey as a true public servant after he concluded a probe of her emails without charges, says Comey’s reopening of the case cost her the election.

Suddenly, Trump says Comey “may have had very good reasons for doing what he did,” but still may force him out.

Other pieces of political sheet music have been exchanged and redistributed as well.

Respect the office of the president, the GOP will now intone.

Suddenly, it comes into the spotlight that under Obama, more than 2 million deportations of immigrants in the U.S. illegally were carried out — and the possibility looms that Trump’s “kick-’em-out” program could be somewhat comparable.

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Suddenly, some Democrats who derided Trump during the campaign as a liar who surely would not keep his promises are actually rooting for him to have been a liar who will not keep his promises.

Suddenly, both Republicans and Democrats who were denouncing Clinton as a puppet of Wall Street are expressing relief that the Dow Jones jumped after Trump’s election.

Suddenly, House Speaker Paul Ryan (R-Wisconsin) and the president-elect seem poised to work out key agreements. Barely a month ago, when Trump trailed in polls, he evoked the idea that Ryan was part of “a whole sinister deal going on.”

Not only have the tunes changed. So have the lyrics.