Immigration raids like the ones expected to start Sunday are nothing new — except for the fact that they’re supposed to be a surprise.

Chalk it up to the increasing political radioactivity of anything touching on the immigration issue — a factor that’s left Congress paralyzed even as US immigration laws, and the whole enforcement apparatus, grow increasingly obsolescent.

This time, it was The New York Times that broke word of when the Immigration and Custom Enforcement raids would start. This round is supposed to target some 2,000 immigrants already ordered to leave.

Yet it was President Trump himself who first tipped off plans last month. “Next week ICE will begin the process of removing” illegal immigrants, he tweeted. “They will be removed as fast as they come in.”

Yielding to a plea from House Speaker Nancy Pelosi, he wound up putting that action off while calling on Congress to start work on closing various loopholes in US law that, for example, have swamped the courts that rule on asylum claims and led to the current crisis on the southern border.

Never mind that such raids have been routine under past presidents of both parties; many Democrats now see any immigration enforcement as inherently unjust. (On Thursday, Pelosi was even issuing advice on how ICE’s targets could avoid arrest.)

Of course, the need for raids themselves is perverse: It flags the system’s overall failure to routinely ensure that those ordered to leave the country actually do so.

So many stay, put down roots and even start families — which makes for some heart-breaking stories when ICE finally catches up.

The left blames all such horrors on the folks trying to enforce the law, but without enforcement the law is meaningless and America might as well just open its borders.

It’s been obvious for decades that this system needs updating: Both sides need to compromise to allow for humane, rational enforcement. The longer the gridlock over reform continues, the worse the horrors will grow.