Trump told Congressional leadership on Friday that he would sign the spending bill despite the tweeted threat, according to reports.
Trump complained about the process of passing the bill at the signing ceremony, pointing to the 2,200 pages next to the podium and saying, "It's just a series of documents nobody has had time to read."
"As a matter of national security, I've signed this omnibus bill…we were forced to, for the military. But I'll never do it again. Nobody read it. It's a few hours old."
Trump repeatedly invoked the need to rebuild the US armed forces to defend his signing of a bill that he was unhappy with.
"For the last 8 years, deep defenses cuts have undermined our national security… hollowed our readiness as a military unit and put America at really grave risk," he said. The president accused Congressional Democrats of putting up "tremendous" opposition to military spending, and complained that he had to trade increased military spending with "wasted" money for Democratic projects.
— Donald J. Trump (@realDonaldTrump) July 20, 2011
Trump called on Congress to end the fillibuster rule, saying without it, budget measures would "get done like magic."
The president continued to blame Democrats for not passing legislation on immigration, even though Senate Republicans have prevented Democrats from bringing a bill to the floor for a vote. "We wanted to include DACA in this bill," he said, but "the Democrats would not do it."
However, US Senate Democratic Whip Dick Durbin (D-IL), asked for consent that the Senate pass the Dream Act on March 22.
"All in all there were six different bipartisan proposals offered to President Trump to solve the problem he created by eliminating DACA. He rejected every single one of them. He sent to the floor of the Senate a bill offered by Senator Grassley of Iowa. Senator Grassley's bill embodied the President's approach to this," said Durbin on Thursday.
"How many votes did the president's proposal get? The president's immigration proposal — 39. The president got 39. It was kind of a shock that the president's own party didn't support the president's bill, at least not all of them."
The White House has said Trump remains concerned about the national debt, which has grown from $20 trillion as of September 8 of last year to $21 trillion as of March 16, the Washington Examiner reported.
The Trump administration has secured about $1.6 billion for the border wall, but Trump said "we're not happy" that so little was allocated for one of his key campaign promises. During the campaign, Trump promised the Mexican government would pay for the cost to build a wall. For her part, Department of Homeland Security Secretary Kirstjen Nielsen, called the money a "down payment" on the wall.