What really struck me, however, was what the platform says about the environment. It opposes any kind of regulation; instead, it argues that we can rely on the courts. Is a giant corporation poisoning the air you breathe or the water you drink? Just sue: “Where damages can be proven and quantified in a court of law, restitution to the injured parties must be required.” Ordinary citizens against teams of high-priced corporate lawyers — what could go wrong?

It’s really hard to believe that young voters who supported Bernie Sanders in the Democratic primary think any of this is a good idea. But Mr. Johnson and Ms. Stein have received essentially no media scrutiny, so that voters have no idea what they stand for. And their parties’ names sound nice: who among us is against liberty? The truth, that the Libertarian Party essentially stands for a return to all the worst abuses of the Gilded Age, is not out there.

Meanwhile, of course, it does make a huge difference which of the two realistic prospects for the presidency wins, and not just because of the difference in their temperaments and the degree to which they respect or have contempt for democratic norms. Their policy positions are drastically different, too.

True, much of what Mr. Trump says is incoherent: in his policy proposals, trillion dollar tax breaks are here today, gone tomorrow, back the day after. But anyone who calls him a “populist” isn’t looking at the general thrust of his ideas, or at whom he has chosen as economic advisers. Mr. Trump’s brain trust, such as it is, is composed of hard-line, right-wing supply-siders — whom even Republican economists have called “charlatans and cranks” — for whom low taxes on the rich are the overwhelming priority.

Meanwhile, Mrs. Clinton has staked out the most progressive policy positions ever advocated by a presidential candidate. There’s no reason to believe that these positions are insincere, that she would revert to 1990s policies in office: What some are now calling the “new liberal economics” has sunk deep roots in the Democratic Party, and dominates the ranks of Mrs. Clinton’s advisers.