President Donald Trump's immigration executive orders — and let's call them what they are: a Muslim ban — represent the first of many constitutional crises that are going to unfold in the Trump era. For Democrats, this has to be a line in the sand: Any and all cooperation with Republicans has got to end, at least until the executive orders are reversed and heads roll for the hell the Trump administration put refugees, immigrants, and their families through this weekend; ideally, all cooperation would cease for the next four years.

President Trump's executive orders on Friday suspended the U.S. Refugee Admissions Program for four months and banned citizens of seven Muslim countries — Iran, Iraq, Libya, Somalia, Sudan, Syria, and Yemen — from entering the U.S. for three months. It also indefinitely shut the door on Syrian refugees entirely. Protests erupted all over the country on Saturday and Sunday; at the Raleigh-Durham International Airport in North Carolina, a protest planned for only 150 people soon exploded into over 1,000 before it was shut down by airport authorities. And on Saturday night, the ACLU won a nationwide temporary injunction against the order from District Court Judge Ann Donnelly in Brooklyn; judges in Massachusetts, Washington, and Virginia also ruled against the order.

In an unprecedented move, however, Trump and his administration simply decided not to comply with the judge's order.

During DHS Secretary John Kelly's confirmation hearing less than three weeks ago, he won rave reviews from some liberals for his stated willingness to break with Trump on several issues; this, however, hasn't been one of them, even as a federal judge orders Kelly's agency to stop enforcing Trump's order. In a surreal scene, multiple Democratic congressmen at Dulles International Airport were unable to speak with Customs and Border Patrol agents, and on Sunday night, Sens. Tammy Duckworth and Dick Durbin of Illinois called for an investigation into the failure to comply with court orders.

It's clear that the worst of Trumpsim will come to pass if the political opposition in this country — meaning both congressional Democrats and people in the streets — don't do something about it. The people are clearly holding up their end of the bargain. But aside from showing up in solidarity, what can elected Democrats actually do?

They can say no. To everything. And they can throw the kitchen sink at Trump in an attempt to grind the gears of government to a near-halt.

Democrats don't have much power, at least not enough to completely shut down the government as Republicans did for 16 days back in 2013. But they do have some. First and foremost, obviously, is the power of votes; given the Republicans' slim majority in the Senate, united Democratic opposition against Trump could be enough to sink any legislation that even three of the more "moderate" (heavy air quotes) members of the Senate Republican caucus are wary of.

The chances of this happening are slim, of course, as Senate Democrats can't even seem to agree on the need to stop Trump's Cabinet appointments. (Kelly's confirmation as secretary of homeland security, by the way, was approved by all but 11 Senate Democrats less than three weeks before his Customs and Border Protection agents decided to defy a federal court's order.) But Democrats can also use blue slips and filibusters to block Trump. In the second term of the Obama administration, Sens. Marco Rubio (R-Fla.) and Richard Burr (R-N.C.) placed holds on judicial nominees they had previously recommended to Obama themselves. Burr also bragged, in a private meeting, that North Carolina had the longest judicial vacancy in history because he felt that Obama broke a promise to him. Flimsy reasoning or not, it's a weapon, and one the Democrats should be using to retain some of the lower court gains they made under Obama. And indeed, it sounds like Democrats are poised to filibuster Trump's Supreme Court nominee.

The filibuster, while weakened by the Democrats back in 2013, looks like it will survive another Congress. Democrats should use it everywhere they possibly can, on fights over health care, voting rights, labor, and whatever other New Deal/Great Society/Obama-era social gains Republicans are preparing to dismantle. As long as Trump stands by his Muslim ban, Democrats must stand up to him — on everything. Thankfully, Senate Democrats are showing signs of life on this front, as they announced on Monday they would filibuster Trump's "stolen" Supreme Court nominee.

Outside of the Senate, Democrats around the country can, and likely will, attempt to stymie Trump through lawsuits. Considering the success Texas and other conservative states had in slowing down some of Obama's executive orders, such as the Clean Power Plan, states led by Democratic governors and attorneys general should take the same steps. It seems that they're ready; the state of California recently hired former Attorney General Eric Holder to represent them in any legal fights against the new administration.

All of this comes with the caveat that elected Democrats' abysmal effort in the first 10 days doesn't indicate that they truly get the dire straits the country — and their party — is in right now. So it appears that if anything at all is going to sink Trump and Trumpism, it will be the erratic president and his administration's utter incompetence, and people taking to the streets to demand a better government.

These mass protests should indicate to elected liberals that the pressure is on to obstruct and delay Trump's agenda in any way they possibly can. And even if, ultimately, the Democratic Party can't be saved, and has to be replaced by a real left opposition party, the Democrats need to fight now. If they don't, the consequences for Muslims, immigrants, the poor, and other marginalized people are going to be apocalyptic in the very near future.

If that's not worth fighting against, what is?