Sen. Thom Tillis (R-N.C.) has told his colleagues in unequivocal terms that he will not vote for the budget reconciliation bill if the Senate considers it this week, according to two people familiar. Why it matters: Tillis' firm opposition to the bill in its current form threatens its passage in the Senate this week.There are other signs that a handful of GOP senators have serious concerns about the $72 billion package, especially the $1 billion for the Secret Service, which includes security upgrades for the East Wing ballroom.A half-dozen senators — including Tillis, Sen. John Curtis (R-Utah), Rand Paul (R-Ky.), Rick Scott (R-Fla.), Susan Collins (R-Maine) and Lisa Murkowski (R-Alaska) — have raised concerns about any funding for the ballroom.Many of them have noted that President Trump insisted the ballroom renovations would be underwritten by private donations.Zoom in: Funding for the Secret Service is currently not in the bill after an unfavorable ruling from the Senate parliamentarian Saturday night.GOP leaders are planning to bring the bill to the floor Thursday, after it passes out of committee Wednesday.The bill is subject to a vote-a-rama, giving Democrats an opportunity to offer amendments — including on the ballroom — that could be uncomfortable for Republicans, especially lawmakers who are up for reelection.A Tillis spokesperson did not immediately respond to a request for comment.Between the lines: Tillis is fuming over the ouster of incumbent Sen. Bill Cassidy in Louisiana's GOP primary — and he's warning that pushing a bill right now would hurt Sen. John Cornyn in Texas' GOP primary runoff next week.Tillis believes Cornyn should be free to campaign in Texas this week instead of being in D.C. for votes.