The Senate parliamentarian ruled late Saturday against a $1 billion provision in the Republican budget reconciliation package designated to fund a new White House ballroom, dealing an immediate setback to one of President Trump's favored budget additions.

The ruling bars the line item under the Byrd Rule, which prohibits reconciliation provisions that lack a primary budgetary effect — a standard the parliamentarian determined the ballroom funding did not meet.

The provision had drawn scrutiny from Senate Democrats and fiscal watchdog groups since it surfaced in the package earlier this month. Critics argued the expenditure had no place in a reconciliation bill designed around tax and spending policy.

Senate Republicans can move to overrule the parliamentarian's decision on the floor, a step that requires a simple majority vote, or accept the ruling and drop the provision entirely. Neither path has been publicly committed to by GOP leadership as of Sunday morning.

The White House did not issue a public statement on the ruling by press time.

The Senate is expected to continue floor debate on the reconciliation package this week, with a final vote on the broader bill still being negotiated among Republican holdouts.