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

Dan Janison has been a columnist at Newsday since 2007.

President Donald Trump faces another deflating loss for his agenda in Congress and thus another blow to his status as a leader.

Republican Sens. Lindsey Graham of South Carolina and Bill Cassidy of Louisiana last week kept pushing their measure to end Obamacare.

But on Friday, Sen. John McCain (R-Ariz.) dealt the bill a staggering blow by saying he won’t deliver a much-needed vote for it.

Even if the legislation rose phoenixlike and prevailed in the Senate this week, the health care travails would resume. House of Representatives approval would be far from clinched. One reason: The clear divide between red-state winners and blue-state losers that the legislation would create.

The Avelere Health analysis widely quoted by policymakers shows California losing $78 billion, and New York $45 billion, in Medicaid funding. They were among the states that accepted an expansion in the program under Obamacare.

Both are “blue” states — but with millions of conservative voters living in them.

Neither leading lawmakers nor Trump ever has answered crucial questions about how a new, improved health care system would work and whether those with pre-existing conditions could afford coverage.

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The minute Congress and Trump succeeded in repealing and replacing the current insurance system, they’d co-own a new system — and all its accompanying flaws.

Even winning in this case could mean losing for the White House, which will bear political blame for anything short of the government-backed “insurance for everybody” Trump promised.

On Aug. 12, Trump taunted on Twitter: “Can you believe that Mitch McConnell, who has screamed Repeal & Replace for 7 years, couldn’t get it done. Must Repeal & Replace Obamacare!”

Trump could have encouraged Congress to move on to dealing with taxes. He chose this course.

Rep. Peter King (R-Seaford), a Trump supporter, said that in “getting what they see as a national consensus,” Graham and Cassidy “had to appeal to the rural states at the expense of the urban, suburban states like New York.”

King said he didn’t see himself voting for the health care bill in the House.

To rack up a win or two, Trump might need to establish an actual leadership role within the GOP. Democratic President Jimmy Carter’s legacy fared poorly when Congress — run by his own party — didn’t carry out his wishes.

Given their mutual hostilities, can Trump really count on Majority Leader McConnell, or House Speaker Paul Ryan, to make the president look successful?

Perhaps there’s tactical wisdom behind the recently privatized former White House adviser Steve Bannon pushing to elect a new crop of Trump-loyal congressional Republicans. It may be Trump’s only chance for pliant partners.