WASHINGTON — The Senate parliamentarian ruled Wednesday that Republicans may include $1 billion in White House ballroom security funding in their reconciliation package, provided every senator swears under oath that the ornate, chandeliered, 30,000-square-foot event space is not, in fact, a ballroom.

The ruling offers a narrow path forward for the stalled funding request, which has divided the GOP conference. To comply with Senate rules, lawmakers must formally reclassify the structure as a “horizontal elevator lobby,” “an unusually large coat-check antechamber,” or simply “the room where dancing categorically does not occur.”

Majority Leader John Thune called the decision a breakthrough. “We are fully prepared to perjure ourselves architecturally,” he said. “This body has a long and storied tradition of calling things whatever we need to call them to make the math work.”

The parliamentarian’s guidance specifies that no senator may refer to the space as a ballroom during floor debate, in written correspondence, or while physically inside the room waltzing.