The Senate may be headed for delays in passing its National Defense Authorization Act this month, with Republican senators saying they will not allow the bill to move forward if full debate isn’t allowed.

Debate on the bill began Monday evening, and by Tuesday majority leadership appeared interested in allowing amendments only on two hot-button topics.

But Sen. Jeff Sessions (R-Ala.) said Tuesday morning on the floor that Senate Republicans wouldn’t allow the massive defense bill–which allows for $526.6 billion in the Defense Department base budget, $80.7 billion for overseas operations and $17.8 billion for national security programs in the Energy Department–to move forward without a healthy debate on a wider range of topics.

Sessions said Senate Majority Leader Harry Reid (D-Nev.) had already “filled the tree,” meaning he limited the number of opportunities to offer amendments and then filled those spots with amendments of his own. Reid said Tuesday he wanted to debate detainee transfers from Guantanamo Bay and reforms to the military justice system and sexual assault response in particular, but he implied that would be the extent of the amendments allowed.

“I would say to Sen. Reid…you should not attempt this dramatic reduction in the ability of the Senate to actually have amendments to a bill as large and as important as the defense bill,” he said on the floor. Without a legitimate debate period, he added, “you’re not going to go forward.”

Reid, however, said Tuesday morning that “if we had votes on those two measures, I think the bill would be ready to go to conference” with the House. Asked early Tuesday afternoon if any amendments not related to Guantanamo Bay or sexual assault would see a vote this week, Reid simply replied, “we’ll see.”

The Senate spent Tuesday afternoon debating the two competing measures on Guantanamo Bay–one offered by Senate Armed Services Committee chairman Carl Levin (D-Mich.) and Sens. John McCain (R-Ariz.) and Dianne Feinstein (D-Calif.), and the other offered by SASC member Kelly Ayotte (R-N.H.). Reid allowed for one of his amendment slots to be replaced by these two bills side-by-side.

Wednesday would be devoted to debating two competing amendments dealing with sexual assault in the military, Reid said.

Despite the uncertainty regarding whether Reid would allow full-Senate debates on other amendments, Levin asked Tuesday morning that his colleagues in the Senate continue to offer “as many relevant amendments to the bill as possible,” vowing to work with the SASC majority and minority staffs to clear amendments so as to be able to offer pre-approved packages of amendments for simpler passage.