In the decade since President Vladimir Putin of Russia directed a sweeping campaign of hacking and social media messaging to try to tilt the 2016 presidential election toward his preferred candidate, the United States has rightly focused on shoring up our elections against foreign meddling.

But I fear that foreign interference is no longer the most pressing danger to our elections. It is increasingly evident that the greatest threat now comes from inside our own government.

For months, President Trump has made his intentions clear. He has called for the federal government to “take over” elections, impose national rules and override state authority. Now we are beginning to see how he may plan to do this.

According to recent reporting in The Washington Post, allies of Mr. Trump’s working in coordination with people close to the White House have circulated a draft executive order that would declare a national emergency based on false claims of foreign interference in the 2020 election. That declaration would be used to unlock sweeping presidential powers over how Americans vote.

The proposal would allow the federal government to bar widely used voting methods, including mail ballots. It would force Americans to reregister to vote on short notice, requiring proof of citizenship. It would insert federal agencies into the voter verification process in novel ways. And it would attempt to override the constitutional role of states in administering elections.

And that is just what is envisioned by the draft executive order. Further steps could be justified, at least on paper, by invoking emergency powers. The president could also attempt to seize voting machines under the guise of a national security investigation. Federal agents could be deployed to polling places in the name of election integrity, intimidating voters rather than protecting them. Entire categories of lawful ballots could be seized or discarded based on unsubstantiated claims of interference.