Most state license plates bear mottos that are uplifting (“The Spirit of America,” “Live Free or Die,”), descriptive (“10,000 Lakes,” “America’s Dairyland”), or welcoming (“Aloha State,” “Great Faces, Great Places”). Only the District of Columbia’s is bad-tempered. The epigram on its license plate is a complaint: “Taxation Without Representation.”)

Washington, D.C., is the nation’s 20th largest city by population and the 122nd largest by area, but it’s the only one that complains because it’s not a state. The license-plate logo is meant to be a protest that D.C. residents pay federal taxes but don’t elect voting representatives to Congress.

Unfortunately for the protesters, crabby slogans don’t trump the Constitution. Statehood for the nation’s capital is barred by Article I, Section 8, which provides that the “seat of government of the United States” is to be located in a unique federal district, on landed ceded by one or more states, in which Congress is “to exercise exclusive legislation in all cases whatsoever.”

The Founding Fathers rejected the idea that the nation’s capital should be in one of the states. As James Madison explained in Federalist No. 43, they wanted the federal government free of any “dependence” on a particular state government for its day-to-day needs and infrastructure. They were determined to protect Congress, the president, and the Supreme Court from being blackmailed or bullied by local officials or militia. Without its own separate federal district, wrote Madison, the federal government “might be insulted and its proceedings be interrupted with impunity.” The Founders had learned that lesson the hard way in Philadelphia, and the Constitution made sure it wouldn’t happen again.

Nonetheless, District politicians and activists have insisted for years that Washington, D.C., ought to be a state, with its own US senators and representative. It has become a popular cause among Democratic politicos. Years ago Jesse Jackson ludicrously called D.C. statehood “the most important civil rights issue facing America” — a claim perhaps explained by the fact that he hoped to be one of the new state’s senators. This year, every Democrat running for president has come out in favor of making the capital city a state, and House Democrats voted in March for a bill that includes pro-statehood language.

But “Democratic politicos” isn’t the same as normal Democrats, most of whom oppose D.C. statehood — just as most Republicans and independents do. A new Gallup poll in July found that 64 percent of Americans are against making Washington, D.C., a separate state. “These results are consistent with past polling on the topic by other firms, which also found majorities opposed to the idea,” Gallup reported. Even when the latest data were broken down by party, ideology, and region, not one major American subgroup supported D.C. statehood.

Americans are not opposed to enlarging the union. Large majorities supported the admission of Alaska and Hawaii for years before they became states, and two-thirds of Americans have consistently said they favor making Puerto Rico the 51st state. But statehood for the District of Columbia? That’s a nonstarter.

Advocates of statehood invariably point out that with a population of roughly 700,000, Washington, D.C., has more residents than some entire states. If Vermont and Wyoming are entitled to two senators and a representative in Congress, demand the statehooders, what justification can there be for disenfranchising D.C.‘s greater population? No justification is needed, of course: The Constitution requires it. But even if it didn’t, the District of Columbia shouldn’t be a state for the obvious reason that it isn’t one. It’s merely a city, and cities have no standing in Congress.

Even the tiniest state by area, Rhode Island, is nearly 20 times the size of Washington, D.C. “Every large state has a multiplicity of interests that must be balanced: agricultural, mining, fishing, banking, insurance, etc.,” notes historian John Steele Gordon. “But the District of Columbia has only one interest: the care and feeding of the federal government. It is the ultimate company town.”

Washington doesn’t resemble a state in any way, and was never supposed to. Any D.C. residents who find “taxation without representation” unbearable are free to move — Maryland and Virginia are no more than two or three miles from any spot within the District. Never has “disenfranchisement” been easier to escape.

But then, the Democratic candidates and other politicians pushing for D.C. statehood aren’t truly interested in voting rights. As everyone knows, what they really crave are the three additional Democratic seats in Congress that would come with a new state.

For anyone who genuinely wants people in the District to be represented in Congress, however, there is no need for statehood. There is a much more straightforward solution: Let the city’s residents to be counted, for federal voting purposes, as citizens of Maryland (the state from which D.C. was carved out in 1791). What could be simpler? While Congress would continue to exercise exclusive rule in Washington, voters living there would be considered Marylanders in House, Senate, and White House election. Presto! No more disenfranchisement, no more taxation without representation, and no more cynical talk of turning a medium-sized city into the 51st state.

The nation’s capital would need a different license plate, though. Perhaps it could say, simply: “Nation’s Capital.”

(Jeff Jacoby is a columnist for The Boston Globe).