It's Democrats who wrote the laws, President Donald Trump argued, trying to explain why his administration is OK with the practice of separating families of undocumented immigrants at the border.

I'd really rather not, but ... these are the laws. Sorry! Change 'em!

"Congress could fix this tomorrow," DHS Secretary Kirstjen Nielsen said in the administration's defense at the White House Monday.

"The children are not being used as a pawn," she later said. "We are trying to protect the children, which is why I'm asking Congress to act."

Nielsen earlier had argued that it would signal the end of American democracy for Trump to continue with a more lenient enforcement policy.

"Surely it is the beginning of the unraveling of democracy when the body who makes the laws, instead of changing them, tells the enforcement body not to enforce the law," said Nielsen.

Never mind that previous administrations and the Trump administration until recently had a very different practice.

It's a riff on the same argument when Trump tried to end the popular Deferred Action for Childhood Arrivals, or DACA, program by which the government had stopped deporting certain people brought to the US illegally as children.

He'd rather not send people raised for years as Americans to countries they don't know, but Congress can't figure out a permanent fix. Sorry!

At the time he announced the end of DACA, he made the decision to do that rather than fight Republican governors who were threatening to sue to stop it. He said he feels for the young people that could be affected. But it would be Congress, not him, who was responsible if a permanent solution couldn't be passed.

"I have a great heart for these folks we're talking about," Trump said back in September of 2017. "A great love for them and people think in terms of children but they're really young adults. I have a love for these people and hopefully now Congress will be able to help them and do it properly."

JUST WATCHED Trump blames Democrats for DACA ending Replay More Videos ... MUST WATCH Trump blames Democrats for DACA ending 02:54

Congress wasn't able to do it properly, and a six-month arbitrary timeline Trump set came and went. The courts have temporarily iced his plans to end it. Washington has been trying for more than a decade, with presidents from both parties and majorities from both parties, to pass comprehensive immigration reform, but neither the pressure of Trump's DACA threat nor his family separation "zero-tolerance" gambit have yet changed the calculus. Moderate Republicans in the House seemed close to a revolt against the status quo over DACA, but it appears to have fizzled for now.

Trump's tactics haven't been isolated to immigration, either. When Republicans couldn't muster the votes to repeal Obamacare on their own, he said that was Democrats' fault too, for not coming to the negotiating table and helping to unravel former President Barack Obama's signature legislative accomplishment.

So he acted unilaterally and did everything he could to strangle the law he couldn't kill, like zeroing out the penalty for not having insurance and also ending government cost-sharing reduction payments to insurance companies. It was a move designed to make premium prices go up. To inflict pain and force Democrats to the negotiating table. We know this is true because he said at the time it'd be Democrats fault when his action had its intended effect.

"Any increase in ObamaCare premiums is the fault of the Democrats for giving us a 'product' that never had a chance of working," he said on Twitter.

In another tweet, he said they should call him to fix the problem but he didn't mention he had made the decision to end the payments on his own.

JUST WATCHED Trump: Obamacare is going to explode Replay More Videos ... MUST WATCH Trump: Obamacare is going to explode 02:14

"The Democrats ObamaCare is imploding. Massive subsidy payments to their pet insurance companies has stopped Dems should call me to fix!"

In announcing tariffs against China, his press team said, they were China's doing, not Trump's. Blame China for any short-term pain and raised consumer prices.

Sanders: "Look, China created this problem, not President Trump. But we finally actually have a president who's willing to stand up and say 'enough is enough, we're gonna stop the unfair trade practices'" https://t.co/yso3WnJsLq — CNN Politics (@CNNPolitics) April 4, 2018

He's promised he won't pass another big omnibus spending bill -- the only kind Congress seems able to pass in recent years. If it comes across his desk, he's said he could veto it.

You can guess who he'll blame if his veto causes a government shutdown. Probably won't be him.

In addition to Trump's willingness to threaten personal pain at the negotiating table, these three examples also share the fact that none of the problems have been solved. That could all change tomorrow, but given the rhetoric from Democrats, who are touring detention centers in Texas rather than calling Trump, it seems more likely these standoffs will continue into November.

The public is against Trump on immigration, but he maintains support among Republicans, according to a new CNN's poll released Monday. Trump learned in 2016 that immigration is a top issue for Republicans. Getting them to the polls will be key if they want to keep majorities in the House or Senate.