It was the best of Warren, and the worst of Warren

If you had any question before Tuesday night’s debate which Democratic presidential candidate is effectively the front-runner, the first half-hour answered it.

Pete Buttigieg went after Elizabeth Warren, wondering why she was so intent on abolishing private health insurance and suggesting her stance would dangerously intensify political polarization in America.

Amy Klobuchar went after Warren, describing her “Medicare for All” plan as one big fat Republican talking point and Warren as a fantasist peddling “a pipe dream.”

Bernie Sanders went after her – well, sort of – by correctly noting her repeated refusal to admit what he already had, which is that Medicare for All would require a tax increase not just for affluent Americans but also for the middle class.

All of this was to be expected. All of it was, in fact, a great compliment to Warren.

During both the opening stretch of the debate and subsequent ones, her prescriptions were the point of reference, her priorities set the terms of the discussion, and she was the candidate to whom the debate’s moderators kept returning so that she could respond to her rivals’ invocations of her.

And she stayed cool and confident under fire, sounding more grateful for the spotlight than fearful of the microscope. It was, for the most part, a fine performance.

But it was also, at first, an exasperating one. That unwillingness to talk candidly about middle-class taxes bordered on perverse.

Why not be explicit about the arithmetic and own it? Warren has campaigned as a truth teller but came across, in this instance, as a classically evasive Washington operator, scared to treat voters as grown-ups who can process information in a sophisticated manner.

Maybe that’s smart politics. But it’s not great leadership.

I loved this debate. OK, maybe “loved” is too strong a word, but I appreciated it, for three main reasons.

One is that Warren’s rivals jousted with her more than before – on health care, on her “wealth tax,” on the way she speaks about corporations and the richest Americans.

That was crucial, because it brought to the surface questions about her ideas that are best recognized and evaluated now, so Democratic voters can figure out if she’s their surest bet against President Trump. It was also important because it gave her a better chance than the previous, gentler debates did to show what she’s made of.

The second reason I appreciated this debate was that it vividly framed the fundamental tension in the Democratic field, the fault line separating Warren and Sanders, for example, from Biden, Buttigieg and Klobuchar.

The latter group of candidates traffic in measured remedies that are more obviously attainable, prioritizing imperfect, incremental change over grandly transformative proposals that face hurdles galore and very long odds.

In their estimation – in mine, too – that’s probably the safer agenda with which to do battle against Trump, whose ouster eclipses all other goals. It’s also the best hope for national healing.

“We cannot wait for purity tests,” Buttigieg said. “We have to just get something done.”

Warren flatly rejected the idea that “some vague campaign that nibbles around the edges of big problems” is a winning formula for Democrats.

The third reason I appreciated this debate is because it so perfectly underscored the most prominent candidates’ rationales for running and arguments for themselves.

Apart from that odd exchange with Warren, Biden had a decent night, partly because he took advantage of several opportunities to stress that he was more prepared for the presidency than anyone else and that the post-Trump era called for someone who wouldn’t have a steep learning curve.

Buttigieg made clear that what he offers, at the tender age of 37, is a truly fresh perspective. He had a superb night, because he embraced a role as Warren’s inquisitor and because several supremely eloquent remarks about foreign policy allowed him to project a command and maturity that some voters needed to see to consider him seriously.

I’d feel remiss if I didn’t note that Sanders, who recently suffered a heart attack, seemed no less vigorous than before.

But Warren, not Sanders, was carrying the progressive mantle Tuesday night, when her less liberal competitors sought with a new assertiveness to trip her up. I don’t think they quite succeeded.