Perhaps President Donald Trump has a plan.

Perhaps he knows exactly what he will do when the old, damaged Hudson River train tunnels fail — as experts fear and expect. When train traffic along Amtrak’s Northeast Corridor, the busiest passenger rail line in the country, grinds to a halt, and vehicle traffic backs up for miles. When people can’t move and businesses can’t transport goods up and down the East Coast. When an area responsible for 20 percent of the nation’s economic activity is paralyzed.

Or, perhaps there is no plan. Perhaps there’s only Trump’s troubling budget proposal to slash existing funds and add zero dollars to the Gateway project, the urgent effort to replace the tunnels, build a new Portal Bridge in New Jersey, and increase capacity at Penn Station. Trump also was wrong to stymie his transportation secretary from allowing the part of Gateway that’s already funded to move forward. All this despite a previous deal for the federal government, and New York and New Jersey, to split the estimated $30 billion cost.

Part of this is personal. Trump sees Sen. Chuck Schumer, who supports the project, as a legislative thorn in his side — and doesn’t want to give the minority leader a win. And part of it is a negotiating tactic: Trump is using Gateway to get what he wants on other issues. But Gateway can’t be a bargaining chip or game piece in a personal battle. And it can’t be a project Trump cavalierly ignores under the pretense that the two states are responsible for tunnels owned by Amtrak, a federally funded railroad.

To spur the healthy economy he rallies around, Trump should support and fund Gateway. Without that, Trump must release a backup plan. If there isn’t one, then Reps. Peter King and Josh Gotteheimer are right to introduce legislation that would force federal officials to develop what they call a “doomsday” plan for the tunnels.

And Schumer and others are right to look for alternative ways to get Gateway done.

But local representatives also must fight to restore and expand federal funding. The two states can’t and shouldn’t do this on their own.

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Trump’s latest budget proposal is a gateway to disaster.

— The editorial board