President Trump’s voter fraud commission has the stated goal of ensuring the integrity of the vote as “the foundation of our democracy.” But, like the buried foundations of a building, who votes and how they vote aren’t easy things to examine.

In alleging that there’s widespread voter fraud, commission Vice Chair Kris Kobach has relied on proxies, such as the indirect measure of matching up names in voter registries to identify people registered in more than one state. In the lead-up to the commission’s second meeting last week, he also railed against thousands of New Hampshire voters who registered using out-of-state licenses — which he claimed proved that people were hopping state borders to illegally swing elections.

The experts I spoke with said those metrics don’t really measure the existence or risk of illegal voting. In fact, they said, it’s probably impossible to conclusively prove or disprove allegations of widespread illegal voting — though they pointed out that very few cases have ever been found and prosecuted, even as Kobach is aggressively seeking them out to prove his hypothesis of rampant voter fraud.

When Kobach employs these proxies as proof of voter fraud, though, he is implicitly suggesting that changes need to be made to the voting system to protect its integrity, such as ensuring that the same name never turns up on multiple registries and voters never use out-of-state licenses at the polls. But those irregularities exist because of the fundamental American values the commission is dedicated to protecting: You can’t easily and swiftly clean up registry errors without disenfranchising millions of voters. And you can’t set up a uniform, nationalized voter registry in a country whose founding values are based on limited federal control.

The problem with proxies is that they do more to demonstrate the complex nature of American values than they do to prove our elections are rigged.

If Kobach were simply claiming that voter registries are messy — full of errors and inaccuracies — he’d be correct. Research published by the Pew Center on the States in 2012 estimated that 24 million registration records (13 percent of all the registrations in the country) contained information that was likely inaccurate — names that had changed, addresses that were no longer up-to-date, people who had died, simple typos. And double-registered voters — a favorite target of Kobach’s — reached nearly 3 million. Likewise, he’s also right that people do sometimes vote in states where they aren’t officially residents. That’s particularly true of college students, who might spend most of their time in a place they don’t technically live. Depending on local laws, those students can use out-of-state licenses to prove their identities at the ballot box.

But experts say that neither of these proxies is particularly good evidence of illegal voting. Primarily, that’s because both things are 100 percent legal and exist for reasons that have nothing to do with fraud. Take double registration, for instance: When Americans are double registered, it’s usually because they’ve moved and their names were never cleared out of the system in their previous state of residence.

We did a quick survey of FiveThirtyEight staffers by checking voter registration rolls in the states they’ve lived in over the past 15 years. Out of 15 people who participated, five were double-registered. I’m one of them, with active voter registrations in Minnesota, where I live, and Alabama, a state I last lived in in 2006. Three staffers were only registered in states they no longer live in. One person wasn’t registered anywhere, much to his surprise. Bottom line: Americans don’t stay in one place forever, and bureaucracy doesn’t always keep up with us.

Then there’s the specter of out-of-state voters. Kobach claimed that more than 5,000 people had come to New Hampshire from other states to vote in (and try to change the outcome of) the November election. His proof was a list of people who had taken advantage of New Hampshire’s same-day registration laws, had used out-of-state driver’s licenses to verify their identities and had not later applied for New Hampshire licenses or vehicle registrations. Kobach has received plenty of pushback on the idea that this meant they weren’t legitimate Granite State voters, including from other members of the commission during last week’s meeting. That’s because it’s likely that many of those people whom he called fraudulent voters were actually college students voting in New Hampshire because that’s where they spent most of their time and where they were living when Election Day rolled around. The Washington Post found several individuals who attested to having done just that, and the cities with the highest number of out-of-state-license voters were college towns.

Just because these practices don’t prove voter fraud, though, doesn’t mean they aren’t confusing and even at times problematic. It’s certainly not ideal to have voter registries loaded with the “dead wood” of misspelled names and people who’ve left the state, said Charles Stewart, professor of political science at MIT. Those errors can prevent people from voting if, say, their current address and registry address don’t match. People in that situation could be turned away or forced to file provisional ballots.

And Stewart said he believes they suggest deeper administrative problems — especially when the state doesn’t know exactly how many errors its voter rolls contain. “What if a school said, ‘We don’t know how many people graduated’? We’d be really suspicious of public officials that had sloppy reporting,” Stewart said. “It’s generally good public policy to have good records.”

That’s why states go through the process of cleaning up voter registration rolls — removing the dead and the people who have left the state to try to maintain an accurate count of voters. But here’s where American values conflict with clean database management: You can’t just unceremoniously purge people from the records because they haven’t voted in a while or because they appear to be registered in another state, said Walter Mebane, professor of political science and statistics at the University of Michigan.

The National Voter Registration Act prevents states from doing just that because it’s likely to end up illegally stripping people of their right to vote. States have to go through a process of trying to match voter registry records to other kinds of data and alerting voters if it looks like they should be removed. There’s no uniform procedure for this, and the quality of registry maintenance (and election administration in general) varies widely from state to state. The courts are still hashing out what is and isn’t appropriate. For instance, the Supreme Court will hear arguments in November in a case on Ohio’s registry maintenance methodology, which purged voters from the rolls if they hadn’t voted in six years.

You could fix the problem — and probably make it easier to see if people have truly double-voted, not just double-registered — by having a single national voter registry, Mebane told me. “But there’s no reason to worry about that because it would never happen,” he said, explaining that it be would anathema to our national values.

Those values strongly favor local control of elections, even when it’s not the most efficient choice. It dates back to the beginnings of the country, when county officials tallied in-person voice votes from citizens who didn’t need to be registered at all. As things like the secret ballot and voter registration were added into the mix, cities, counties and states came up with different ways to handle the new complications, collect the records and administer the elections. Today, elections are governed by states, but a lot of the nuts-and-bolts management still happens at the city or county level — often in ways that vary from one town to another. And shifting away from that diverse local control probably wouldn’t be terribly popular, given that Americans’ confidence in election results and fair handling of votes decreases as the level of administration moves further from where they live.

The same is true with out-of-state voting: You can simplify the system, but that would conflict with other values. Courts have repeatedly said students can vote where they study. “Nobody can lose their right to vote because of issues with residency as a student,” said Marc Meredith, professor of political science at the University of Pennsylvania — something that would be likely to happen if students were forced to travel back to their home states on Election Day in the middle of their fall semesters.

But Americans are generally less supportive of students voting outside their home states than we are of other 20th-century voting reforms, Stewart said. “There’s a sizeable number of people in the public who just believe that college students should vote where their parents live.”

He based that on the unpublished results of questions he asked in the Cooperative Congressional Elections Study in 2013. Although most Americans — 65 percent — said expanding where students could vote improved elections, respondents were less supportive of that than they were about other kinds of reforms — like extending the vote to women.

In other words, Americans are both suspicious of thousands of people from “someplace else” tipping an election and have also set up the legal system to support expansion and protection of the right to vote, even for people who are, technically, from someplace else. The result is a jumble of laws that make the ability of college students to vote — and what forms of ID and documentation they have to bring with them to the polls — vary unpredictably from state to state, even county to county. Even someone like Kobach — a state election official who has made his national career on issues surrounding election transparency — can’t be expected to know what is legal and what isn’t nationwide, experts told me. There’s just too much diversity.

But the data mess explains why it’s difficult to make a case around voter fraud from either side. Just because a situation isn’t ideal doesn’t mean it’s proof of illegal voting. Instead, Meredith said, he wishes Kobach and the commission would focus on finding better ways to systematically study voting — ways that line up with both the needs of researchers and American values. “Your hope would be that’s what a voter integrity commission would be,” he said. “Rather than jumping to conclusions on the basis of proxies that may or may not have validity.”