Civil-rights icon Congressman John Lewis, in an interview with NBC’s Chuck Todd, indicated he didn’t think President-elect Donald Trump would be a “legitimate” president and that he would not be attending his inauguration because Russia conspired to interfere in America’s presidential election.

Prickly—never one to be punched and not punch back—Donald Trump responded with a stereotypical, erroneous tweet about Representative Lewis’s not paying enough attention to his “crime infested” congressional district, “which is in horrible shape and falling apart.” Congressman Lewis represents a booming downtown Atlanta and many thriving middle-class neighborhoods, including the third-largest business district in Atlanta, in Buckhead.

It’s important to distinguish between “legitimate” and “legal.” Congressman Lewis did not say Donald Trump wouldn’t be a legal president. While Trump lost the popular vote by nearly 3 million votes, he did win the presidency legally through the Electoral College.

Coming out of the civil-rights movement, Congressman Lewis has never limited his thinking to a choice between legal and legitimate. He grew up under legal signs that read “white” and “colored” on restaurants, restrooms, and swimming pools, and rode on buses marked colored seat to the rear. They were legal signs, but he didn’t see them as legitimate. American apartheid was legal, but not legitimate!

By what moral authority does Donald Trump, the chief proponent of the racist “birther” accusation intended to delegitimize the first African-American president, Barack Obama, question John Lewis’s saying he sees Trump as an illegitimate president?

And by what moral right do Republicans—led by Senate majority leader Mitch McConnell and Speaker Paul Ryan—challenge John Lewis? They and their Republican colleagues treated President Obama as illegitimate by using a strategy of opposing everything President Obama supported, even it was previously a Republican policy or plan, such as the Affordable Care Act.

But in my mind, Congressman Lewis has triggered a much bigger question. That is, “Has the United States ever elected a legitimate president?”

When George Washington was elected, black slaves, Native Americans, women, and most white men without property weren’t allowed to vote. That was legal, but not legitimate, in terms of a representative democracy. It wasn’t until the 15th Amendment (passed in 1870) that black men were allowed to vote—and that was only legally and theoretically, not in actuality. We were legally electing presidents, but in a so-called democratic representative government of, by, and for the people, we weren’t electing fully legitimate presidents without the participation of slaves, women, Native Americans, and white men without property.

In 1870 women wanted to be included in the outlawing of discrimination in voting in the 15th Amendment, but were opposed by many of the chief abolitionists, including Frederick Douglass. It caused a split in the previously united coalition of abolitionists and suffragettes, and it took another 50 years of struggle, until 1920, to make discrimination in voting against women illegal and unconstitutional. Again, presidential elections before 1920 without the participation of women were legal, but they were not fully legitimate.

It wasn’t until the 1965 Voting Rights Act—which was the enabling legislation for the 15th Amendment, 95 years after ratification—that African Americans and other minorities could, in reality, begin to make progress in registering and voting. That also means that presidential elections up to 1965 were legal, but not truly legitimate, to the degree that law and custom prohibited African Americans and other minorities from voting.

Conventional political and press analysis, including Congressman Lewis’s allegation regarding the 2016 presidential race, has mainly focused on Russian efforts to influence the American election in favor of Trump and against Clinton, and the inappropriate release of FBI Director James Comey’s letter 11 days before the election, which the Clinton campaign’s internal polls showed directly impacted her campaign.

There has been almost no serious focus on the negative effects of the 2013 Supreme Court decision that gutted the 1965 Voting Rights Act, leaving 2016 the first presidential election since 1965 without its full protections. New voting laws that made voting more difficult and Republican voter-suppression efforts targeting specific groups of voters have mostly been ignored. But the suppression of the black vote was a significant factor in Hillary Clinton’s loss.

The United States remains near the bottom of all democratic nations in terms of voter participation. In the most recent election, Trump received the votes of only 26 percent of eligible voters and Clinton received just 28 percent. In our democratic government of, by, and for the people, barely half of the people are participating. Why is there so little voter participation?

Most of the initiative for voter registration and voting rests with individual voters and partisan political parties. The federal government assumes little responsibility for voting and sets virtually no nationally enforceable minimum standards, which results in low registration, little nonpartisan education, or the passage of laws to make it easy and more convenient for voters to vote—e.g., automatic voter registration at age 18, early voting in every state, and national holidays for voting.

Americans aren’t given an individual right to vote by the federal Constitution, so voting is a state right. Therefore, Republican-controlled states in our states’-rights and local-control voting system introduced 395 new voting laws between 2011 and 2015 targeting minorities, women, workers, seniors, young people, and the disabled—i.e., Democrats—and making it more difficult for them to vote.

There is only one way to not only elect legal presidents but legitimate presidents, and that is to have as close to 100 percent voter registration and participation as possible.

And I know of only one way to do that, which is to add a right-to-vote amendment to the US Constitution—i.e., to put the right to vote on the same plane as the Second Amendment’s right to a gun—giving every American an individual right to vote and giving Congress the authority to establish a unified national voting system that has certain common-sense minimum standards that the state- and locally administered voting jurisdictions would have to follow.