There’s a reason New York’s U.S. Sen. Chuck Schumer is near the top of the Democratic Party’s leadership — no position, no matter how unprincipled or demagogic, is a bridge too far for Mr. Schumer if he thinks it will help the Democratic Party come Election Day.

Thus, it’s no surprise that Sen. Schumer has been the foremost voice for a constitutional amendment proposed by New Mexico Sen. Tom Udall to expand Congress’ powers to regulate political speech.

The proposal comes in the wake of Supreme Court decisions like the Citizens United case (which opened the door to super PACs) and a more recent decision striking down aggregate restrictions on how much money donors can give to federal candidates, though limits remain on donations to any individual candidate.

The amendment’s function would be to make explicit the power of the federal government and state governments to pass regulations regarding both how much money donors may give to candidates and how much money may be spent by candidates or those opposing them. At first blush, that may seem benign — but the reality is decidedly more ominous.

Based on the Udall Amendment’s language, you would think that government is presently powerless to regulate campaign spending. That’s hardly the case. The recent Supreme Court decisions may have lightened restrictions at the margins, but campaign finance on both the state and federal level remains a maze of complex and confusing legal strictures. Even the conservative justices who have handed down the opinions have acknowledged that regulating campaign expenditures is a legitimate function of government.

When they have overturned such regulations it has been because they run afoul of the First Amendment’s protections of free speech — which means that the Udall amendment either functions to weaken those restrictions or serves no purpose at all. Even more menacingly, the text of the amendment lumps in “in-kind contributions” with financial ones. That would place any political activity — from organizing a rally to writing a letter to the editor — under the government’s thumb.

Citizens have every right to worry about the corrupting influence of money in politics. The proper response to that impulse is to aggressively prosecute instances of official corruption — not to give incumbent lawmakers sweeping new powers to regulate their competitors.