A marathon voting session on President Donald Trump’s sweeping domestic policy bill is underway in the Senate and has stretched overnight into Tuesday after a weekend of negotiations and delays.

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.

Lawmakers voted largely along party lines to advance the megabill, overcoming weeks of closed-door negotiations and internal disagreements.