President Donald Trump said Tuesday he does not want a government shutdown, but warned that one could give his administration an opportunity to make deep, lasting cuts that opponents would not be able to reverse.

"We can do things during the shutdown that are irreversible, that are bad for them and irreversible by them, like cutting vast numbers of people out, cutting things that they like, cutting programs that they like," Trump told reporters in the Oval Office.

However, he said that Republicans and the White House don't want to shut down the government at midnight.

"We're not shutting it down. We don't want it to shut down because we have the greatest period of time ever," Trump said. "I tell you, we have $17 trillion being invested. So the last person that wants to shut down is us."

Still, Trump cautioned that a lapse in funding could allow him to slash federal programs in ways his critics would oppose.

The president praised Office of Management and Budget Director Russell Vought, who has advocated aggressive spending reductions. 

"He can trim the budget to a level that you couldn't do any other way," said Trump.

The president also accused Democrats of pushing for federal health coverage for people in the country illegally, pointing to policies backed by California Gov. Gavin Newsom.

"That's, I would say, the No. 1 reason that they want to strike — to get illegal immigrants healthcare," Trump said. "And, you know, Gavin Newsom wants that too, in California. And it's destroying California. We can't have that. We're not going to let it happen."

Trump also broadened his criticism, charging that Democrats want "tremendous amounts of money for healthcare for people that aren't even citizens," including those entering the country from "prisons, jails, and mental institutions."

He said disputes extend beyond immigration, citing fights over transgender medical procedures, men in women's sports, and what he called Democrats' "open borders" agenda.

"Our country was dead one year ago. Now we have the hottest country anywhere in the world," Trump said. "It says a lot about the state of the Democrat Party when they have a 33% favorability rating on average in recent months, and they're willing to shut down the government over healthcare."

• Mike Johnson to Newsmax: ACA Subsidies Not Shutdown Issue
• Rep. Lawler to Newsmax: Shutdown an 'Unforced Error' by Dems