Memo to Democrats: The United States is at war and vulnerable to terrorist attacks; this is no time to be defunding Homeland Security.

Democrats have been withholding funding for the Department of Homeland Security for weeks in hopes of forcing Republicans to agree to all but gut ICE.

Yet now the United States and Israel have struck Iran, and Americans face the threat that terrorists sympathetic to Tehran and/or hostile to this country snuck in during the Biden open-border era and may see this as the time to strike.

Already, a seemingly Islamist madman shot up a bar in Austin, Texas, on Sunday: Folowing the joint US and Israeli air attack, Senegalese immigrant Ndiaga Diagne — wearing a “Property of Allah” sweatshirt and a t-shirt embossed with a tribute to the Iranian flag — murdered at least two people and wounded another 14.

Such an act could be a sign of things to come, as “lone wolves” or Iranian sleeper cells awaken to carry out savage violence against Americans.

So why are Dems still holding up funding for DHS, the agency tasked with finding and neutralizing terrorists in the homeland?

Fixated on defanging ICE as part of their midterm electoral strategy, Senate Democrats have refused to end this partial shutdown — which only affects DHS agencies including TSA, Border Patrol and the Secret Service, though ironically not ICE — unless Republicans cave on their radical wish list.

Never mind that the GOP has already agreed to some of the Dems’ demands. Body cams for ICE agents, for example, have gotten the OK, and Republican leadership has expressed openness to limiting random stops of suspicious vehicles.

But that’s not enough. The Dem also demand, among several other things, a mask ban for ICE officers, which won’t happen so long as leftwing officials and activists encourage followers to dox, harass and even harm agents and their families.

Meanwhile, TSA agents, DHS officers and even the Secret Service are working without pay; these are committed civil servants dedicated to their mission, and are surely doing their best to defend the homeland.

But at a time like this, it’s beyond nuts to treat these vital workers like that, especially just to make a political point.

Democrats may feel gratified that their radical wing is sticking it to ICE, but their cheap stunt could wind up being very expensive for the rest of us.