For U.S. Sen. Susan Collins, the $1.5 trillion tax overhaul is a mixed bag.

The Maine Republican, who voted for the Senate version last week, said late Monday the bill “is by no means perfect and it’s not the bill I would have drafted.”

But, she said, it offers hope for tax relief that’s worth pursuing.

With both a House and a Senate version on the table, a joint committee is working behind closed doors to come up with a proposal that mashes the two together so that both houses of Congress can pass the same bill to send on to President Donald Trump. Legislative leaders have said they plan to get it done before Christmas.

Collins said she prefers parts of each bill, but the Senate one includes a number of provisions that she convinced supporters to put in as they wooed her to secure her vote for the bill, which passed the GOP-controlled Senate along party lines.

Along with every Democrat in the Senate, U.S. Sen. Angus King, a Maine independent, rejected the tax bill as a rushed and ill-considered proposal.

Betsy Sweet, a Democratic gubernatorial hopeful, said Collins’ vote “was entirely about party loyalty and not at all an effort to make Mainers’ lives better.”

She called it “a collection of two decades’ worth of the GOP’s worst insults, lining the silk pockets of the super-rich while doing absolutely nothing for working families.”

But Collins said her decision was on the merits, despite some misgivings.

One element of the bill she doesn’t like is the Senate’s call to make a big reduction in corporate taxes permanent while allowing the cuts for individuals to expire in less than a decade.

“It doesn’t make sense to give more to the corporate side,” Collins said. She said that people “should be upset” that lawmakers aren’t treating ordinary people with the same generosity they’re showing businesses.

Collins said the House bill, which doesn’t have an expiration date for either, is a better option.

To make the financing work, she said, perhaps legislators should take up Trump’s offer to reduce corporate taxes from 35 to 22 percent on profits instead of aiming for 20 percent.

Collins also said it is “a big mistake” for the Senate measure to include efforts to revise the Affordable Care Act by wiping out the individual mandate that requires everyone to have health insurance or pay a fine.

She said she pushed to remove the provision but once it became evident it was going to stay in the bill she pressed for other changes she argues will help lower premiums and keep insurers in the market.

Collins said dropping the fines for people who don’t want to participate is quite different from axing the program entirely.

The important thing, she said, is to make sure that people who “have it, want it and need it” can get affordable coverage.

The senator said she’s never supported the individual mandate because she’d rather take steps to encourage people to have insurance than force them to buy policies they don’t want or pay fines they can’t afford.

Collins pointed out that 80 percent of the people fined for failing to have coverage earned less than $50,000 annually — low and middle-income households that need the money for something else.

She said a better answer is to “lower premiums” that are more costly than they ought to be. Senate and administration officials promised her “we would pass” by year’s end two measures she thinks will help lower the tab and bolster the health insurance marketplace.

There is, however, growing evidence that the House won’t go along with the provisions Collins is seeking to help preserve the ACA.

Those include one that would pump $5 billion into a program to help states create high-risk pools that ought to lower premiums by as much as 20 percent, she said. The pools would be used to help insurers cover the most expensive patients, something Maine did back in 2012 with success and which Alaska is using now.

The other, the Bipartisan Health Care Stabilization Act, would provide funding in 2019 and 2020 to allow cost-sharing reductions for low-income people enrolled in ACA exchanges.

Though the Congressional Budget Office estimates that dropping the mandate will result in 13 million fewer Americans with health insurance a decade from now, Collins said she’s not convinced. She said the CBO is going to use a new forecasting model next year that “will show far less numbers” without insurance going forward.

In any case, Collins said, it would be better for everyone if government switched the way it gets people insured by enrolling everyone in a plan and then letting those who don’t want it opt out. She said the opt-out model winds up with more people insured than the existing system that requires people to choose to be included.

At its heart, though, the tax bill is getting a bad rap from opponents, Collins said.

She said some of the things she managed to get into it helped improve it.

For one, she said, making the child tax credit partially refundable puts more money into the hands of some who really need it.

For example, Collins said, a single mother earning $35,000 annually will get $1,100 back “that she can use to make ends meet” because the credit isn’t applied solely to what she would owe. If it exceeds her tax bill, the senator said, she’d get a check from the government.

Collins said she worked hand in hand with the senior-focused AARP to provide help for taxpayers with high medical expenses who aren’t reimbursed by insurance or Medicare. Most of them are seniors with long-term-care needs, the senator said.

Under existing law, they can take a medical deduction on their taxes after they’ve spent 10 percent of their income, Collins said. The House bill would wipe that out.

But Collins got the Senate bill to include the provision and to make it more generous than it is now, lowering the threshold to 7.5 percent of income before someone can deduct medical expenses.

Collins said she also received assurances from Senate Majority Leader Mitch McConnell, R-Ky., and House Speaker Paul Ryan, R-Wis., that if the tax cut’s impact on revenues winds up draining too much money from federal coffers, they won’t cut anything from Medicare.

Reducing Medicare “would be disastrous,” Collins said, and she is confident that it won’t happen.

Collins also got the Senate bill to allow for property tax deductions up to $10,000 for those who itemize on their tax forms.

Since Maine has the 11th-highest property tax burden in the nation, Collins said, “this will be helpful to a lot of middle-income families.”

Because the standard deduction is slated to go up, however, there are likely to be many fewer households citing particular deductions as part of their tax filing if the tax overhaul is approved.

Collins said she also made sure that public employees would be able to make catch-up contributions to their retirement plans, something the bill deleted “for reasons not obvious to me.”

“We should be encouraging people to save more,” she said, not taking steps to make it harder on them.

Taken as a whole, she said, the tax bill will offer relief for many while simplifying the process for most families. It will also spur the creation of more good jobs and economic growth, she said.

Collins said she’s hearing from many Mainers on the proposal, pro and con, and is convinced that it’s worth moving ahead on it.

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U.S. Sen. Susan Collins (AP)