The White House’s push to delay a ban on intoxicating hemp products that President Trump signed into law last year has snarled an otherwise straightforward effort to pass legislation that would lock in government funding through the fall before senators leave Washington on a summer recess.
In an unusual display of defiance, a group of Republicans led by Senator Ted Budd of North Carolina was vowing to kill the hemp proposal that Senate leaders had tucked into the spending bill at the request of Mr. Trump.
The measure would postpone the date the ban will go into effect, from November to Dec. 11.
“This is about protecting kids, and keeping it off the shelves,” Mr. Budd said in a brief interview. “These illicit products that are finding their way into North Carolina stores and North Carolina kids’ hands.”
Earlier this week, it appeared that the bipartisan Senate spending legislation, which would keep federal funding flowing at current levels through early December and bar the Trump administration from transferring funds to the Border Patrol, was on a glide path. Senators voted on Monday by a lopsided margin, 89 to 4, to advance it.
But G.O.P. opposition to the hemp measure is now imperiling efforts to quickly pass the legislation. Senate leaders typically rely on bipartisan deals that require the consent of all senators to help speed the passage of bills and bypass time-consuming procedural hurdles.
Opponents of the hemp measure insist it cannot remain in the bill. They are irate about both the policy, which they argue allows the unregulated sale of dangerous products that are intentionally marketed to children, and the process by which it made its way into the spending package, as a last-minute insert into a must-pass piece of legislation.
Complicating matters further is that the delay stands to benefit the son-in-law of Susie Wiles, Mr. Trump’s chief of staff.
The animosity flared on Wednesday during a closed-door luncheon of G.O.P. senators, where James Braid, Mr. Trump’s legislative affairs chief, made the case for the provision and promised opponents that the White House would not seek any further postponements.
But Mr. Braid did not appear to sway some of the proposal’s most ardent critics, and the luncheon devolved into a series of heated and testy exchanges, according to people familiar with the meeting.
“He knows where I stand,” Mr. Budd said of Mr. Braid after the gathering. A spokesman for Mr. Budd said that the senator also had “a friendly phone call” with Mr. Trump on Tuesday in which he reiterated his concerns.
The president signed the ban into law last year as part of a broader spending bill to reopen the government after a record-long shutdown.
Senate G.O.P. leaders are also juggling a number of other agenda items before leaving for their August recess, including confirming Mr. Trump’s nominee for attorney general, Todd Blanche, and efforts to consider a bill aimed at regulating college sports.