Tangential, but this is a great example of a fabricated wedge issue in American politics. The solution is so simple, just issue everyone a free national ID card. Passports should be free too and could also double for this purpose. Then the Republicans can stop complaining about voter fraud and Democrats can stop complaining about voter disenfranchisement (the latter of these I am legitimately concerned about, I just wish someone would actually follow through and do something about it).
Also, it's ridiculous that there isn't a national holiday at least on the day of the presidential elections.
(In addition, imagine an interest group instituting a "we'll pay your poll tax for you!" campaign, but only in counties carefully selected for demographics.)
One possible sequence:
1) Trump fever sweeps Rs to power in 38 state legislatures two years from now.
2) Those legislatures pander to morons by passing a Constitutional Amendment barring those without physician-issued certificates of femininity from women's restrooms.
3) Millions of Californians take to the streets in protest for weeks at a time, unable to accept life under what comes to be called "wrong-partheid".
4) Desperate business owners cast about for some way to get everyone back to work, and hit upon secession. A plebiscite is called, and with 90% of California citizens voting, every county except Modoc and Lassen vote to secede. Those counties petition Oregon for admission, but are turned down and have to join Nevada instead. Then Las Vegas has a vote to secede from Nevada, but last-minute distributions of maps illustrating where the water comes from cause secession to fail.
At this point, Trump could send in the Army to enforce the Union, but I really hope he doesn't. If he did, many soldiers would refuse the order, and many generals would push for some other solution. Perhaps California will bribe Trump with some real estate deals. They can write it into their new constitution to make sure it's legal.
After that I would hope for many more secessions. This nation needs to be drastically shrunken to put all the lobbyists out of business.
Predictably, nonwhite voters tended to be failed.
But I agree with the other commenter, selecting the questions in a fair way would be challenging.
There's also the problem that many jurisdictions have 2+ elections each year. A federal poll tax would create quite a bit of room for local poll taxes that would be that much more abusive.