Let’s be honest with ourselves: The new Democratic majority in the House won’t be able to enact new legislation. I’ll be astonished if there are bipartisan deals on anything important — even on infrastructure, where both sides claim to want action but what the G.O.P. really wants is an excuse to privatize public assets.

So the immediate consequences of the power shift in Washington won’t involve actual policymaking; they’ll come mainly from Democrats’ new, subpoena-power-armed ability to investigate the fetid swamp of Trumpian corruption.

But that doesn’t mean that Democrats should ignore policy issues. On the contrary, the party should spend the next two years figuring out what, exactly, it will try to do if it gains policymaking power in 2021. Which brings me to the big policy slogan of the moment: the so-called Green New Deal. Is this actually a good idea?

Yes, it is. But it’s important to go beyond the appealing slogan, and hash out many of the details. You don’t want to be like the Republicans, who spent years talking big about repealing Obamacare, but never worked out a realistic alternative.