President Trump on Friday signed a bipartisan bill on border security and declared a national emergency to get the money for his long-promised southern border wall that Congress wouldn’t give him.

“We’re going to be signing [the bill] today and registering a national emergency, and it’s a great thing to do, because we have an invasion of drugs, an invasion of gangs, an invasion of people and it’s unacceptable,” Trump said outside the White House.

“It’s not like it is complicated. It’s very simple. We want to stop drugs from coming into our country. We want to stop criminals and gangs from coming into our country.”

Trump did not sign the bill or the declaration in public, saying he would do it back in the White House.

The president began by repeating his talking points in favor of a wall — and rejected the federal government’s own statistics that show most illegal drugs coming across the southern border come in through ports of entry.

“One of the things I said I have to do and I want to do is border security because we have tremendous amounts of drugs flowing into our country, much of it coming from the southern border,” the president said.

“When you look and when you listen to politicians, in particular certain Democrats, they say it all comes through the port of entry. It’s wrong. It’s just a lie. It’s all a lie. They say walls don’t work. Walls work 100 percent,” he continued.

And he bitterly attacked House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer.

“They go through areas where you have no wall. Everybody knows that. Nancy knows it. Chuck knows it. They all know it. It’s all a big lie. It’s a big con game. You don’t have to be very smart to know. You put up a barrier, the people don’t come in and that’s it,” he said outside the White House.

Prior to the announcement, Trump recited a list of what he said were his accomplishments on dealing with China, North Korea and the UK post-Brexit.

He also boasted about the economy and military spending.

Later, he introduced Angel families, those who lost a loved one to murder, drunken driving and other crimes committed by illegal immigrants.

A senior administration official said Trump would seek $8 billion for 234 miles of bollard fencing identical to that already in place.

Trump spoke after Congress resoundingly approved a border security compromise that averted a second painful government shutdown.

Trump’s plan to bypass lawmakers and declare a national emergency to siphon billions of dollars from other federal coffers for his wall on the Mexican boundary faces opposition by Democrats and some Republicans.

But Trump confidently predicted he would prevail in any court fight.

Money in the bill for border barriers, about $1.4 billion, was far below the $5.7 billion Trump insisted he needed and would finance just a quarter of the 200-plus miles he had demanded.

Democrats vowed to fight the move.

In a joint statement, Pelosi and Schumer said the declaration would be “a lawless act, a gross abuse of the power of the presidency and a desperate attempt to distract” from Trump’s failure to force Mexico to pay for the wall, as he’s promised for years.

“Congress will defend our constitutional authorities,” they said. They declined to say whether that meant lawsuits or votes on resolutions to prevent Trump from unilaterally shifting money to wall-building, with aides saying they’d wait to see what he does.

Democratic state attorneys general said they’d consider legal action to block Trump.

Puerto Rico Gov. Ricardo Rossello told the president on Twitter “we’ll see you in court” if he makes the declaration.

With wires