U.S. Sen. Susan Collins was right to not endorse candidate Donald Trump for the presidency, and she was right to call for Trump to release his tax returns.

Collins was right to vote against a GOP bill that would have repealed Obamacare, and in mid-November she was right to criticize the Senate’s “tax reform” package because it would repeal Obamacare’s individual mandate, driving up insurance costs for thousands of Mainers, many of whom would likely lose medical coverage altogether.

But then after President Trump and the Senate Majority Leader Mitch McConnell, neither of whom has earned her trust, offered her assurances that two separate bills to stabilize health insurance markets would be passed, Collins caved.

Once she decided to remain in the Senate and not run for governor of Maine, she apparently began looking for ways to endear herself to her GOP Senate colleagues. Voting for the Senate’s tax bill was an easy way to get back in her GOP colleagues’ good graces.

The clearest evidence that she sought to win back her GOP friends was the flip-flopping on her earlier calls for keeping the estate tax as is and denying tax cuts to those Americans making more than $1 million per year. The final bill doubled the estate tax deduction, and it decreased the income tax on millionaires.

After flip-flopping on those two demands, she decided to support the Senate’s tax bill upon securing several amendments. Instead of eliminating the property tax deduction, the final version capped and commingled it with a state and local tax deduction at $10,000. Collins asked for and got a reduction in the deduction threshold for medical expenses. Collins asked for and got a provision to allow “catch-up contributions” to retirement accounts of charities, churches, and school and public employees.

Collins also got assurances that two bills to stabilize the health insurance market in exchange for her apparent acceptance of the repeal of Obamacare’s individual mandate. But both bills only provide temporary relief in the insurance market, with the Collins-Nelson bill providing for only 2018 and 2019 federal funds for state reinsurance programs to offset premium increases for ill low- and middle-income folks. By her own reckoning, as she pointed out last month, ending the individual mandate will cancel the value of tax cuts for middle-income earners.

Now that Collins has voted to pass the final version of the tax bill, Collins has once again crossed her own red lines. Like a lemming, she has joined the GOP tribe to take a fatal leap of faith in the mistaken belief that giving more than $1 trillion in tax relief to wealthy individuals and huge corporations will somehow stimulate an already highly stimulated economy.

Collins must be deeply conflicted. Throughout the legislative process, she has evinced the natural Maine proclivity to be an independent thinker and actor, to resist the herd instinct that both parties try to engender among their members, and to watch out for the poor and vulnerable in Maine.

But in the end she caved.

Long known as a “moderate Republican,” her input into the “tax reform” legislation shows she is just as much a conservative Democrat. Perhaps she should follow the example of Angus King — leave the GOP, declare that she is henceforth an independent but caucus with the Republicans.

By so doing, she escapes the sad dilemma of trying to serve two masters: the people of Maine and her GOP Senate chums. When in doubt, Collins, should choose the former over the latter.

Roger Bowen is author of “Innocence is Not Enough.” He lives in Prospect Harbor.

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