The government has been shut down since midnight Tuesday because lawmakers can’t agree on a continuing resolution (CR) to fund the government. House Republicans have tried to attach riders to defund and delay ObamaCare, but Senate Democrats have said they would only accept a “clean” CR.

Casey pointed to the fact that more than 70 percent of civilian intelligence workers were furloughed because of the shutdown.

“You cannot stop terrorism and arm yourself against terrorist unless you have the full information,” Casey said. “There are a number of reasons we should act to reverse the government shutdown but none is more compelling than national security.”

It's unclear where the fight will go from here, with both sides digging in for the first government shutdown since 1997.