WASHINGTON — Republican House Speaker Mike Johnson predicted Monday the federal government shutdown may become the longest in history, saying he “won’t negotiate” with Democrats until they hit pause on their health care demands and reopen.

Standing alone at the Capitol on the 13th day of the shutdown, the speaker said he was unaware of the details of the thousands of federal workers being fired by the Trump administration. It’s a highly unusual mass layoff widely seen as way to seize on the shutdown to reduce the scope of government. Vice President JD Vance has warned of “painful” cuts ahead, even as employee unions sue.

“We’re barreling toward one of the longest shutdowns in American history,” Johnson of Louisiana said.

With no endgame in sight, the shutdown is expected to roll on for the unforeseeable future. The closure has halted routine government operations, shuttered Smithsonian museums and other landmark cultural institutions and left airports scrambling with flight disruptions, all injecting more uncertainty into an already precarious economy.

The House is out of legislative session, with Johnson refusing to recall lawmakers back to Washington, while the Senate, closed Monday for the federal holiday, will return to work Tuesday. But senators are stuck in a cul-de-sac of failed votes as Democrats refuse to relent on their health care demands.

Johnson thanked President Donald Trump for ensuring military personnel are paid this week, which removed one main pressure point that may have pushed the parties to the negotiating table. The Coast Guard is also receiving pay, a senior administration official confirmed Monday. The official insisted on anonymity to discuss plans that have yet to be formally rolled out.

At its core, the shutdown is a debate over health care policy — particularly the Affordable Care Act subsidies that are expiring for millions of Americans who rely on government aid to purchase their own health insurance policies on the Obamacare exchanges. Democrats demand the subsidies be extended, but Republicans argue the issue can be dealt with later.

House Democratic leader Hakeem Jeffries said with Republicans having essentially shut down the chamber now for a fourth week, no real negotiations are underway. They’re “nowhere to be found,” he said on MSNBC.

With Congress and the White House stalemated, some are eyeing the end of the month as the next potential deadline to reopen government.

Open enrollment begins Nov. 1 for the health program at issue, and Americans will face the prospect of skyrocketing insurance premiums. The Kaiser Family Foundation has estimated that monthly costs would double if Congress fails to renew the subsidy payments that expire Dec. 31.