U.S. Senate Republicans were struggling to pass President Donald Trump's sweeping tax-cut and spending bill early on Tuesday, amid deep divisions within the party about its expected $3.3 trillion hit to the nation's debt pile.

With Sens. Rand Paul and Thom Tillis opposed to the package, GOP leaders can afford only one more defection. And multiple Republicans aren't yet sold on the measure.

Senate Republicans employ an unusual accounting tactic to push Trump's tax bill forward, sparking concerns over national debt and the integrity of the Senate filibuster.