Senate Republicans moved closer Thursday to passing a sweeping $1.4 trillion tax-cut package that would slash rates on corporations, lower rates on many individuals and eliminate state and local tax deductibility.

The bill got a major boost when possible holdout Sen. John McCain announced his support.

“I believe this legislation, though far from perfect, would enhance American competitiveness, boost the economy and provide long overdue tax relief for middle-class families,” he said in a statement.

The last time the Senate tried to pass major legislation — a ­repeal of ObamaCare — McCain (R-Ariz)( cast a dramatic “no” vote that sank the bill.

Senate Majority Leader Mitch McConnell (R-Ky.) was confident he’ll get the votes this time.

“We’re on the cusp of a great victory for the country and particularly for small business,” McConnell said as the Senate met into the night.

But sticking points remained.

Some deficit hawks — like Sens. Bob Corker (R-Tenn.) and Jeff Flake (R-Ariz.) — wanted to craft a trigger mechanism to automatically increase taxes if the overhaul doesn’t raise projected revenues via a growing economy.

The trigger idea started to fall apart Thursday evening for running afoul of Senate parliamentary rules.

Adding to the concerns of the fiscal hawks was a new report from the Joint Committee on Taxation projecting that the tax measure would spur only about 0.8 percent in GDP growth over the decade and widen the deficit by $1 trillion.

Sen. Ted Cruz (R-Texas) said he would have a “serious problem” with any plan that sets off higher taxes. Instead, he said he wants another trigger to prompt more tax decreases if revenues come in greater than planned.

Another critical swing vote, GOP Sen. Susan Collins of Maine, said she couldn’t support the bill unless it restored property-tax deductions of up to $10,000, like in the House tax bill.

“That is something I have to have in the bill,” Collins said.

She also sought assurances that legislation would be enacted to stabilize health-care markets.

Other issues under discussion included if the 20 percent corporate tax rate might be raised, the extent of the child-tax credit, and the tax rate for small businesses.

Sen. Thom Tillis (R-NC) said he hoped senators wouldn’t get too bogged down with amendments and would pass something that can be improved in conference committee with the House.

President Trump has said he wants to sign the final legislation by Christmas.