The Washington Post reports: “A crucial GOP senator is raising questions about the bill after finding out that it includes a tax break that could financially benefit him and politically tarnish him.

“Sen. Bob Corker, R-Tenn., says he wasn’t aware of this new tax break for wealthy real estate developers like him, but the left is whacking him for initially withholding support, yet later backing the bill around the same time that this provision was included.” We have no reason to doubt Corker, who says he had nothing to do with inclusion of the provision. CNN explained, “According to (Sen. Orrin) Hatch, Corker and his staff never contacted the Senate Finance Committee about including the provision. Hatch said that instead, the provision was merely a result of combining the House and Senate tax bills, which both structured taxes for pass-through entities like real estate LLCs differently.”

However, Corker’s alleged mendacity is not the issue. Rather, the question now is: Knowing that this provision is included and that the bill is just as fiscally irresponsible as the version he voted against, how could he vote for the bill anyway? Over several days we’ve asked Corker’s office that question and have yet to get a responsive answer. It’s curious to say that he was concerned enough about the debt to vote “no” on the bill last time but not this time. What happened between now and then?

We can speculate on the reasons – political peer pressure, self-interest, keeping a political future alive, the potential absence of two Republican senators because of health concerns, etc.

Politico reports: ” ‘On one hand, you had the deficit issue. On the other hand, you had the economic growth issue,’ Corker said. ‘I took a long walk on Friday morning and just decided that from the standpoint of, if I were the deciding vote on this . . . is our country better with this or not better with it? And I feel that we are.’ ”

But it is up to Corker to explain to the country and his constituents why he disagrees with virtually every independent assessment saying long-term growth will not make up for the increase in the deficit; why he couldn’t have tried to force the Senate to start anew with a revenue-neutral corporate tax bill; why the offending real estate tax break should remain in the bill; and why he thinks it’s necessary to skew so much of the tax relief to the super-rich.

Likewise, Sen. Susan Collins, R-Maine – who recently vowed to stay in the Senate to continue to be “a bridge between the two sides . . . (when) fewer and fewer senators enjoy playing that role” – could have led the way in forcing senators to work on a bipartisan bill, one more fiscally responsible and less generous to the super-rich. Instead of being a bridge to Democrats, she allowed Republicans to dig in their heels.

Collins has been taking a pounding from health care advocates as well as local and regional media.

In other words, her central promise to protect health care exchanges went overboard in favor of talking points on growth. (In announcing her decision, a statement from her office insisted, “Senator Collins secured the commitment of Majority Leader Mitch McConnell to pass two important bills before the end of the year to mitigate health insurance premium increases caused by the repeal of the (Affordable Care Act’s) individual mandate. Senator McConnell promised to support passage of both Alexander-Murray, a proposal to help low-income families afford insurance, and Senator Collins’ bipartisan bill to protect people with pre-existing conditions through the use of high-risk pools.”)

In fact, there is zero evidence that McConnell will deliver – House Republicans oppose the so-called health care stabilization bills, and Collins announced Wednesday that they are being withdrawn and resubmitted for votes in 2018 – and she voted for the tax reform bill anyway.

A cleaner tax bill with fewer hidden surprises such as the real estate provision would be more likely to promote tax fairness and growth. A bill without repeal of the individual mandate would have preserved the health care exchanges that Collins vowed to stabilize.

That Corker and Collins nevertheless chose not to stand firm, but instead go with the herd stampeding toward an ill-conceived bill that was never the subject of serious, open hearings, remains a mystery and source of disappointment for those who expected conviction, not collapse, when the chips were down.

We can only conclude that those expectations – fed by these senators’ rhetoric and self-description as “moderates” – were misplaced.