When the gang at Mar-a-Lago rings in the New Year Monday night, the posh Florida club's most prominent member will be missing: President Donald Trump.

Mick Mulvaney, director of the Office of Management and Budget and the incoming chief of staff, says the president will stay in Washington to work on ending the week-long government shutdown.

"The President's been here, by the way, all weekend, all Christmas," Mulvaney said in an interview on "Fox & Friends." "He's staying in Washington, D.C., over New Year's. He's canceled his plans for Christmas. Now, he's canceled his plans for New Year's."

Mulvaney says the president is "very heavily engaged on (the shutdown negotiations) on a minute-by-minute basis."

If so, he's not getting a lot of face time with members of Congress, who have all, by and large, gone home for the holidays.

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Since the partial federal shutdown began, the president's only break from lone White House duty was a quick trip to Iraq with first lady Melania Trump to visit U.S. troops last week.

The first lady, who jetted up from Florida for the trans-Atlantic trip, returned to Florida afterward for the New Year's celebrations.

Even the president's daughter, Ivanka, and son-in-law, Jared Kushner, left town for the holidays.

Indeed, Trump — who tweeted in his first days of post-shutdown duty that "I am all alone (poor me)" — sounded almost wistful again Saturday in a morning tweet: "I am in the White House waiting for the Democrats to come on over and make a deal on Border Security."

"From what I hear," he added, "they are spending so much time on Presidential Harassment that they have little time left for things like stopping crime and our military!"

But the president did take advantage of the slow holiday pace to make a few phone calls, noting that he "just had a long and very good call with President Xi of China."

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If it's any consolation, Xi is also unlikely to be celebrating on Dec. 31.

The Chinese New Year isn't until Feb. 5.