President Donald Trump mocked Democrats Thursday for refusing to act on the southern border crisis, forcing him to declare a national emergency.

“The Democrats are ‘Border Deniers,'” Trump wrote on Twitter. “They refuse to see or acknowledge the Death, Crime, Drugs and Human Trafficking at our Southern Border!”

The president declared a national emergency in February, but Democrats responded by passing a resolution to block it.

The Senate is expected to vote on the resolution on Thursday. Five Senate Republicans are expected to join Senate Democrats, which would cause the resolution to pass.

Republican Sens. Mike Lee, Susan Collins, Lisa Murkowski, Rand Paul, and Thomas Tillis have indicated they will oppose the president.

Trump repeated his promise to veto the resolution if it got to his desk.

“I am prepared to veto, if necessary,” he wrote. “The Southern Border is a National Security and Humanitarian Nightmare, but it can be easily fixed!”

The Democrats are “Border Deniers.” They refuse to see or acknowledge the Death, Crime, Drugs and Human Trafficking at our Southern Border! — Donald J. Trump (@realDonaldTrump) March 14, 2019