In a tweet late Wednesday night, US President Donald Trump conceded that he would not deliver his State of the Union speech until after the partial federal shutdown is ended. The tweet acknowledged that the invitation to the president to address a joint session of Congress in the chamber of the House of Representatives is the “prerogative” of House Speaker Nancy Pelosi.

On Wednesday afternoon, Pelosi officially withdrew her invitation to Trump to deliver the State of the Union speech, as the conflict over the partial shutdown of the federal government escalated to unprecedented dimensions. Her action came in response to a letter from the White House in which Trump said he would not agree to a postponement of the State of the Union address because of the federal shutdown and would deliver the speech as scheduled on January 29.

The House speaker indicated that while she had extended Trump the usual invitation to deliver the State of Union when she took office on January 3, she had not imagined that the partial shutdown of the federal government, which began on December 22, would still be ongoing at the end of January.

The formal invitation to address a joint session of the House and Senate requires passage of a concurrent resolution by the Senate, now controlled by the Republican Party, and the House, where Democrats took control on January 3. Pelosi’s letter reads: “I am writing to inform you that the House of Representatives will not consider a concurrent resolution authorizing the President’s State of the Union address in the House Chamber until the government has opened.”

Trump’s initial reaction was an intensification of his vindictive and authoritarian denunciations of the Democratic Party. “I’m not surprised,” he told the press. “It’s really a shame what’s happening with the Democrats. They’ve become radicalized. They don’t want to see crime stopped.”

He said of Pelosi, “She’s afraid of the super-left Democrats, the radical Democrats. What’s going on in that party is shocking.” He added that the withdrawal of the invitation was “a great blotch on the great country we all love.”

White House deputy press secretary Hogan Gridley, speaking on Fox News Tuesday, the day before the actual withdrawal of the invitation, implicitly compared the Democratic Party to ISIS terrorists, saying, “If the Secret Service can protect the president of the United States on a trip to Iraq, chances are they can protect the American president in the halls of Congress.”

The cancellation of the State of the Union address would be a landmark event in American politics. These addresses have been delivered by the president to a joint session of Congress since 1913, when Woodrow Wilson broke with the previous practice of sending a written message to provide the accounting that is required by the US Constitution.

Only once has a State of the Union address been postponed—in 1987, when the space shuttle Challenger blew up shortly after launch only a few hours before President Ronald Reagan was to deliver the address. Reagan made remarks on the disaster from the Oval Office and delayed the State of the Union address by a week.

Even after the House of Representatives had impeached President Bill Clinton in December 1998, and he was awaiting trial before the US Senate, Clinton gave a State of the Union address in January 1999 in the same House chamber where the impeachment vote had been taken only a month before.

But the current crisis of the US political system has reached such a level of intensity that such rituals are now in question, as the conflict between the Trump administration and its opponents within the corporate elite heads into previously unknown territory.

The cause of this conflict is not simply differences over the border wall or immigration policy as a whole. The Democratic Party is seeking to strike a compromise with the White House that will give Trump the substance of his policy, so long as he does not use the label “border wall” to describe it.

This is indicated by the statements of House Majority Leader Steny Hoyer and Representative Bennie Thompson, chairman of the House Homeland Security Committee, that the Democrats are preparing to offer Trump the $5.7 billion he is demanding for border security, provided he agrees to reopen the federal government.

Leading Democrats described the offer as including drones, reinforced security at ports of entry, and more money for sensors, fence repairs and border guards, but not a fixed structure. The number three Democrat, House Majority Whip James Clyburn, said, “Using the figure the president put on the table, if his $5.7 billion is about border security, then we see ourselves fulfilling that request, only doing it with what I like to call using a smart wall.”

A more right-wing section of Democrats is prepared to go even further. A letter circulated by Representative Elaine Luria, a former Navy commander just elected to a House seat in Virginia, calls on Pelosi to make a deal with Trump to exchange wall funding for protections for DACA and TPS recipients, sections of immigrants whose federal protection has been lifted by Trump. The letter calls for seeking “bipartisan solutions” that would provide both “the true needs of border security and… much-needed reform to our immigration process.”

The House voted by 234–180 Wednesday to enact legislation adding $1.5 billion more for border security, including new immigration judges and infrastructure, above the $1.3 billion already approved for the Department of Homeland Security. Senate Majority Leader Mitch McConnell has already dismissed the bill, saying he will not bring it up for a vote in the Senate unless Trump gives his backing.

Democratic Representative Tom Malinowski, a former State Department official newly elected to a New Jersey congressional seat, confirmed the spinelessness of the Democrats, declaring, “From my standpoint, and I think this is the consensus of the caucus, everything is negotiable. Border security is negotiable. Immigration policy is negotiable. Shutting down the government is not negotiable, and we’re angry about it.”

Trump has rejected every proposed compromise in order to press forward with the federal shutdown. In a particularly provocative move, Senator McConnell has introduced legislation that would implement Trump’s offer of last Saturday, of a wall for DACA, but with significant modifications that would effectively gut the right of asylum. Under the plan, children under 18 from Central America would be barred from applying for asylum at the US-Mexico border, and would instead have to do so at US embassies in Honduras, Guatemala and El Salvador, the home countries which they are fleeing because of gang violence and state repression. The bill, which is likely to be blocked in the Senate on Thursday, would also cap child refugee admissions at 15,000 a year, no matter how many qualified.

Such provocative demands suggest that Trump has no real interest in settling the conflict over immigration policy. The shutdown is not, in his view, an obstacle to be overcome, but a positive development--a tactic to be employed to bully his way to achieving many other policy objectives. Certainly from the standpoint of big business, shutting down regulatory agencies like the Environmental Protection Agency, the Food and Drug Administration, the Department of Agriculture and the Department of the Interior, or social service agencies like the Department of Housing and Urban Development, are long-sought goals.