So much for the optimistic spin that the Russia probe will be wrapped up "soon."

Despite Trump’s claim last December that special counsel Robert Mueller was nearing the end of his investigation, the White House is now quietly preparing for a much longer probe.

On Monday, the so-called budget released by Trump’s own team even acknowledged that, setting aside another $10 million for the investigation to march on into 2019.

“The budget projects that Mueller’s team will keep spending at its current rate of about $10 million per year in the next fiscal year, which starts in October,” Politico reported after the White House unveiled its $1.5 trillion blueprint.

In terms of Mueller’s budget and the estimated $10 million cost for 2019, a spending report released by the special counsel’s office in December detailed that the probe had spent $3.2 million between May and September.

This dollars-and-cents estimate, of course, counters months’ worth of spin suggesting Mueller and his large team of lawyers were wrapping things up and any unpleasantness for Trump would soon be behind him.

White House spokesman Raj Shah told Fox News last month that officials “believe [the investigation] will end soon” — calling back to last October, when press secretary Sarah Huckabee Sanders announced Mueller’s work would likely be concluded “soon.”

Hardly.

Mueller’s team has a criminal case pending against Trump’s former campaign chairman Paul Manafort and deputy Rick Gates. That trial is expected to begin in August or September.

But that’s likely just a run-up to the main event, which could focus on Trump and his top White House aides.

Indeed, the looming showdown between Mueller’s office and Trump continues to unfold, with Trump’s attorneys desperate to keep him from testifying for fear he’ll open himself up to criminal charges by lying to prosecutors.

In recent days, the Justice Department’s No. 3 attorney, Rachel Brand, abruptly left her post, reportedly concerned that she could be asked to oversee Mueller’s investigation if Trump took the extraordinary step of firing Deputy Attorney General Rod Rosenstein.

Mueller had already made it clear in December that his investigation would last at least through 2018. And despite the stubborn wishes of Trump and his surrogates, it seems the White House has resigned itself to an even longer timeline.