A harsh reality began setting into Capitol Hill on Tuesday: The U.S. government may not reopen until the two parties reach a deal to raise the national debt ceiling.

Hours after federal agencies shuttered their doors for the first time in nearly two decades, congressional leaders from both parties began to prepare for a protracted budget battle bound to grow more difficult the longer it goes unresolved.

Indeed, if the standoff continues to creep toward the Oct. 17 deadline to raise the $16.7 trillion national debt ceiling, the two issues will become intertwined — and potentially intractable. House Republican leaders and top Senate Democrats privately began discussing this increasingly likely possibility Tuesday, but the two sides have yet to engage in any direct negotiations in the acrimonious budget dispute. …

“This is now all together,” Senate Majority Whip Dick Durbin (D-Ill.) said of the debt limit and the continuing resolution to keep the government funded.