What’s this ruckus on the hustings? The Democrats suddenly seem to be of two minds about the plan to co-opt the Electoral College — the National Popular Vote Compact. “I think all of us know the Electoral College needs to go,” Governor Walz declared on Tuesday at a Coast fundraiser. A campaign flack quickly overruled him, explaining that wasn’t the Harris-Walz ticket’s official position. It’s hard to just sweep the idea under the rug, though.

The Trump campaign pounced on Mr. Walz’s gaffe — unless it’s more accurate to call it a trial balloon — asking, via social media, why the Minnesota governor hates “the Constitution so much?” That could overstate the case, though — at least, according to the backers of the interstate compact. They contend that it’s constitutionally kosher for each state to choose to allot its electors to the winner of the national popular vote.

The constitution does, indeed, ordain that “Each State shall appoint, in such Manner as the Legislature thereof may direct, a Number of Electors.” What’s to stop them from appointing electors based on who wins the most votes nationwide? Critics point to the Constitutional prohibition on any state to “enter into any Agreement or Compact with another State,” without the say-so of Congress. That legislative okay would be an iffy proposition.

Mr. Walz is one such proponent of the National Popular Vote plan, the Times points out, noting that just last year he signed into law a measure that brought Minnesota into the interstate compact. The scheme’s advocates contend, if the compact goes into effect, “it will apply the one-person-one-vote principle to presidential elections, and make every vote equal.” The first step is signing up enough states to make a majority in the Electoral College.

This method of instructing electors has been simmering for years. One of its most eloquent supporters, Hendrik Hertzberg, notes that one of its merits is that it would work, as he puts it,  “without changing a word of the Constitution.” So far 18 states, the most recent being Maine, have signed on, and the pact, including the Columbia District, has 209 electoral votes. So but a handful of states, with electoral 61 votes, are needed to seal the deal.

The appeal of the National Popular Vote effort is understandable for Democrats who, two times since 2000, lost the presidency despite racking up a majority of votes nationally. Mr. Walz’s remarks would appear to reflect the anxiety that this pattern could repeat itself on November 5, with Democrats scoring large vote margins in blue states and cities like California and New York, while the GOP ekes out narrow wins in a few critical swing states.

Adopting the National Popular Vote compact would go a ways “toward making the United States of America something more closely resembling a modern democracy,” Mr. Hertzberg avers. The Framers, though, desired to dodge the dangers of direct democracy when they crafted the Electoral College contraption. Why, after all, didn’t they arrange for the commander in chief to be chosen by a majority of votes cast nationwide on Election Day?

The indirect process of choosing a president through the Electoral College, “first and foremost,” these columns explained a few weeks ago, “preserves a role for the states in our federal system.” That’s in contrast with the tendency on the left to see the states as mere administrative appendages of the federal leviathan. In this view the states are just geographic departments for parceling out pork-barrel spending according to formulas devised by beltway bureaucrats.

Seen through the constitutional lens, though, the states are sovereign entities who only joined the union with an assurance that their rights would be preserved by a limited federal government. The guaranteed preservation of each state’s two votes in the Senate — another bête noir of the left — is one of the safeguards of their sovereignty. The electoral college is another defense against federal overreach. No wonder Democrats seem so keen to drop it.