Last month, Colorado’s legislature became the twelfth to pass the National Popular Vote Interstate Compact (NPVIC,) an agreement among the states to circumvent the constitutional method of electing the president in favor of a national popular vote. Each state that signs the agreement would require its presidential electors to obey the results of the national popular vote, not the results in their own state. It would come into effect when states representing a majority of electoral votes have signed on to the idea. Colorado Gov. Jared Polis, a Democrat, has pledged to sign the bill.

The idea has been capturing the attention of frustrated Democrats since law professor Robert W. Bennett dreamed it up after the 2000 election. It gained even more popularity on the left in 2016, following the election of Donald Trump despite Hillary Clinton’s popular vote plurality.

As an antidote to the Democratic Party’s current difficulties in winning votes outside of their coastal base, the compact is bound to appeal to fed-up partisans. But as a legal matter, it is flawed and almost certainly unconstitutional.

The Constitution Can Be Changed Only by Amendment

The way we change constitutional requirements like the Electoral College is detailed in Article V of the U.S. Constitution. The amendment process described there gives several ways to change the Constitution, and may be used to bring about nearly any alteration the people desire. It was, in fact, used to alter the Electoral College process three times before.

The first, in the Twelfth Amendment, approved in 1804, mandated that electors vote separately for president and vice president (before then, the vice president was the runner-up in the presidential election, a system that quickly became untenable). The Fourteenth Amendment, added in 1868, barred unpardoned rebels from becoming electors and requiring that states allow all of their male citizens over 21 years old to vote for electors (with a minor few exceptions). The Twenty-Third Amendment expanded the Electoral College to give the District of Columbia three electors in 1961. In addition, the Fifteenth, Nineteenth, Twenty-Fourth, and Twenty-Sixth Amendments expanded the right to vote generally, including in presidential elections.

As all this makes clear, we are perfectly capable of altering the method of presidential election through the amendment process, and have done so often in our history. Why, then, would the advocates of a national popular vote not use that tried-and-true method of altering our political structures legitimately? The reason is simple: they have tried it before and failed. Instead of trying to build popular support, popular vote advocates are now trying to get around the law through this legislative sleight of hand.

It takes more to amend the Constitution than it does to pass a simple statute, and purposely so. The Constitution is supreme over all other laws and state constitutions. As such, changes to it ought to be something that more than a bare majority desires. Laws come and go, but a Constitution is meant to have staying power and not be idly altered.

The popular vote campaign does not have that widespread support. Time and again, amendments proposed in Congress to accomplish their desired result have failed. A quick look at the states that have joined this legally dubious effort shows that the effort is entirely one-sided—the compact has been made law in Maryland, New Jersey, Illinois, Hawaii, Washington, Massachusetts, Vermont, California, Rhode Island, New York, and Connecticut, as well as the District of Columbia.

None of these states have voted Republican in a presidential election since at least 1988. In fact, D.C. has never voted Republican, and Hawaii has done so only twice. The addition of Colorado will mark the first time that anything close to a swing state has joined the compact—Colorado voted Republican in 2004, and favored Hillary Clinton by less than 5 percent in 2016.

A narrowly partisan change to the Constitution is not likely to pass, nor should it. The changes to the Electoral College made in the 1804 and 1961 amendments had widespread support around the country, and corrected problems that nearly everyone agreed were problems. The NPVIC does not seek to remedy such an ill; it seeks victory for one side through changes in the law.

This Interstate Compact Violates the Constitution

It is a bad idea, but does that mean it is unconstitutional? Not on those grounds alone, but the compact clearly violates the plain language of several sections of the Constitution. The first clue is in its title. Any interstate compact must raise the issue of the Compact Clause in Article I of the Constitution, which holds in relevant part that “No State shall, without the Consent of Congress … enter into any Agreement or Compact with another State.”

That’s a pretty strong statement. No penumbras and emanations here, only the unequivocal language of the Constitution that says any compact among the states must be approved by Congress. Even in those analyses of the NPVIC that support its constitutionality , authors admit that “read literally, this provision would require all agreements between states to be approved by both houses of Congress and to be signed by the President before coming into effect.”

“Read literally.” What other way should a law be read? Do the NPVIC’s advocates think the language is metaphorical? Do they suppose the Constitution’s authors were being whimsical when they wrote this phrase? Even originalists can admit that some passages in the Constitution are vague, but to read the words any way other than literally invites us to have no standard at all.

Non-literalists point to historical examples of agreements between states that never received congressional approval, yet have never been invalidated. Most of these involved border adjustments between two states, a necessity in the days of imprecise measurements. Drawing on an 1893 Supreme Court ruling in Virginia v. Tennessee , they maintain that Congress does not need to approve all compacts, only those involving “the formation of any combination tending to the increase of political power in the States, which may encroach upon or interfere with the just supremacy of the United States.”

This is taken as evidence in the NPVIC’s favor, but it is more naturally read the other way. Even if the carve-out invented in Virginia v. Tennessee remains good law, it suggests only that minor agreements with no effect on the union as a whole should be exempt from congressional approval.

The exact contours of the Virginia-Tennessee border (the subject of that case) do not change the balance of power between the states and the federal government. While important to people living along that state line, it has no federal implications and is hardly even a compact; it is merely the clarification of an earlier (in this case, colonial) agreement on a physical boundary.

Compare that to the NPVIC, which effectively rewrites an entire section of the Constitution. The compromises struck at Philadelphia in 1787 were not made lightly. Decisions on how the president would be elected and how many votes each state would get are the product of lengthy negotiations and trade-offs. To overturn those arrangements based on the alliance of a few states—likely not even a majority of them—turns that finely balanced design on its head.

A compact among these states that will determine the election of the president is the farthest thing from the minute adjustments to a colonial-era state border. The Constitution provides one method of electing a president, while the NPVIC substitutes another. Nothing could be more of an encroachment upon “the just supremacy of the United States.”

Disenfranchising Their Own Citizens

Other constitutional objections could also hinder the NPVIC. One of the biggest issues is that, while claiming to value all Americans’ right to vote for president, the compact has the effect of disenfranchising each state’s citizens.

Imagine a scenario like the 2004 election, where Republican George W. Bush won a majority of the popular vote, but did not win any of the current NPVIC member states (Colorado will be the exception to this rule when it joins the compact). The result would have been that John Kerry’s ten best states all cast their votes for his Republican opponent. Does that make any sense? Is that the will of the voters in those states?

The concern is more than moral. The Fourteenth Amendment, as noted earlier, made a change to the Electoral College meant to address the former Confederate states’ efforts to disenfranchise their newly freed black citizens. Section 2 of that amendment holds that:

Representatives shall be apportioned among the several States according to their respective numbers, counting the whole number of persons in each State, excluding Indians not taxed. But when the right to vote at any election for the choice of electors for President and Vice President of the United States, Representatives in Congress, the Executive and Judicial officers of a State, or the members of the Legislature thereof, is denied to any of the male inhabitants of such State, being twenty-one years of age, and citizens of the United States, or in any way abridged, except for participation in rebellion, or other crime, the basis of representation therein shall be reduced in the proportion which the number of such male citizens shall bear to the whole number of male citizens twenty-one years of age in such State.

In layman’s terms: if any state denies the right of adult male citizens to vote, that state’s representation in the House of Representatives will be reduced in proportion to the percentage of such men who were disenfranchised. That is, if the state of Louisiana—which was 50.1 percent black in 1870—had refused to allow its black citizens to vote, the number of representatives Louisiana could send to Congress would be reduced by 50.1 percent.

Despite widespread black disenfranchisement in the South following the end of Reconstruction, this provision was never enforced. It nevertheless remains valid law, and the read together with the Nineteenth and Twenty-Sixth Amendments, it would likely prevent the disenfranchisement of any citizen aged 18 or older. The Congress that passed this amendment sought to protect the former slaves from being deprived of the right to vote; they never imagined that a state would someday attempt to disenfranchise all of its citizens.

Yet that is clearly what the NPVIC threatens to do in removing the right to vote for electors for president. If the nationwide vote is won by a candidate other than the one who won in that state, the state’s electors would nevertheless vote for that candidate. This would sever the connection between the voters and the electors, disenfranchising the people and jeopardizing the state’s representation in the House.

Fantasy Elections

Even if the NPVIC were constitutional, and even if enough states joined it to bring it into effect, there is no guarantee that the result would suit Democrats any better than the current system. We don’t know who would have won a national popular vote contest in 2016 because no one, at present, has ever tried to win one.

Any campaign worth its salt tries to win the actual election, not the fantasy election we call the popular vote. Republicans do not campaign in California, even though citizens of that state cast 4,483,810 votes for Trump in 2016, more than any state except Florida and Texas. Likewise, Democrats do not waste much time or money in Texas in presidential elections, even though Clinton got more votes out of the Lone Star State than any state but three. (Clinton also did not expend much effort in much closer states like Wisconsin and Michigan.)

Could Trump have gotten more votes out of California if his campaign had spent time and resources there to get out the vote? Of course he could, but it would not have been enough to overcome Clinton’s massive advantage there, so they did not bother. At the same time, many conservative Californians likely sat home, knowing their votes would not tip the state to Trump. This is the heart of the NPVIC advocates’ case for a popular vote, yet they fail to see how it cuts against them just as much. We don’t know who would win a national popular vote, because we’ve never really had one.

Losing two elections in the Electoral College despite popular vote pluralities is bound to frustrate partisans on the left, and it has seemingly driven some of them to embrace radical, nonsensical solutions. Emotions run high in electoral politics, but they cannot overcome the truth of what the Constitution does and does not allow. Proponents of a popular vote are free to amend the Constitution if they can but until they do so, they must respect the rule of law and accept the results of elections.