THE DEMOCRATIC EMPHASIS ON PURITY TESTS MIGHT HELP ELECT A REPUBLICAN

Jonathan Bernstein has a point about last night's debate:

The first hour of tonight's debate between Bernie Sanders and Hillary Clinton was full of fireworks.... But it was also, I'm fairly sure, the least policy-specific hour of a Democratic presidential debate ever.

Instead, the candidates debated ideology, party loyalty, the nature of power in a capitalist system, and other generalizations. They spent an inordinate time (egged on by the MSNBC moderators) discussing what counts toward being a "progressive"...

In other words, they sounded a lot like Republicans. I mean, without the sideshow.

... typical of that first half hour, however, was Sanders's blanket statement that " the business model of Wall Street is fraud." It's a great applause line, at least for the target audience, just as railing against "amnesty" is a great applause line in Republican debates....

Trouble is, none of the big talk gets done without someone who can write, pass and implement workable plans.

Okay, that last sentence is where I deviate somewhat from Bernstein. I think Bernie Sanders is entitled to argue that it's realistic to demand the impossible, even without a concrete plan to attain the impossible, because maybe you push the Overton window to the left, and what used to be seen as an unattainable progressive goal becomes at last partly attainable.

What concerns me about reducing even part of a Democratic debate to a purity test is that the time spent talking about purity isn't being used to define the candidates as what they are -- namely, well to the left of the extremely conservative Republicans. We'd see this if we looked at their policy positions, but we're spending a lot of time not looking at their policy positions, and looking instead at the abstract concept of purity. Yes, Sanders is further to the left than Clinton on most issues. But both Democrats are solidly on the left, while the Republicans are far to the right.

Take capital gains taxes. Yes, Bernie Sanders wants to tax capital gains as ordinary income, which would be a big increase in the tax, one that would fall largely on the wealthy; by contrast, Hillary Clinton would raise the capital gains tax only on profits made on assets held from one to two years (there's already a higher rate for gains on assets held for a year or less).

That's a much more modest increase -- but it's still an increase. CNBC's Larry Kudlow calls the plan "inconceivably stupid," which, if you're a liberal, ought to convince you that it's an excellent idea.

By contrast, here's what would happen to the capital gains tax if the guy a lot of people think has the inside track for the Republican nominations gets elected and has his way:

... the once-fringe idea of abolishing a capital-gains tax is going mainstream this year courtesy of Senator Marco Rubio....

His plan would impose no tax at all on interest, dividends or capital gain income from stocks. It would also set a maximum tax rate of 25 percent on business income, both for large corporations and small ones. In many cases, that would mean business owners would pay a lower tax rate on profits than their employees would pay on their wages -- even after counting both taxes paid by the business and those paid by the business owner directly.

This is why it infuriates me to get mired in these purity wars. Obviously Sanders is much more progressive than Clinton. But just as obviously, either of them would be immensely preferable to the radically right-wing Republicans. If the specifics aren't discussed, voters don't see that. They just see a binary debate: progressive or not progressive, with "not progressive" coming to be perceived as indistinguishable from "conservative."

Let's get back to talking about specifics. Otherwise we risk demotivating the Democratic base in the (still likely) event that Hillary Clinton is the nominee.