You should carefully examine the evidence you have supporting that belief. Start by observing that this is a partisan issue in which the official positions of the two major parties disagree on a factual claim, not merely the policy. A disagreement on policy can (sometimes) be chalked up to a difference in values, even though those do sometimes arise downstream of factual incorrectness. But a disagreement on facts is one with in which someone is right and someone is wrong. (Or, more complicatedly, someone is closer to accurate and someone is cherry-picking.)

If what you believe to be true is in fact true, then you should be able to comfortably go searching for evidence to falsify it and support the alternative, and fail to find such evidence, confident in your assumption that you won't find it. Either way, I hope that you desire to find the correct answer rather than the one that would be convenient for your political position, and that whatever hypothesis you have has not set itself up to be unfalsifiable.

> they are doing everything they can to ensure that only the people who are legally allowed to vote are the ones voting

Illegal voting is so rare that almost every time folks go looking for it they come up empty handed. Examples of voter suppression, on the other hand, are trivial to fine. (And both parties do it, particularly around primaries.)

In my state, we’re trying to enact a citizenship-proof requirement which penalizes women who change their name on getting married and those who can’t afford a passport. In effect, a marriage and poll tax. Ironically, this will disenfranchise the MAGA voters who are themselves pushing for it, but I’m not really going to point that out aggressively.

(That said, a legitimate fraction of American politics right now is in convincing the other side’s likely voters that elections are rigged, the oligarchs are in charge, why even bother calling your electeds or voting, eat an ice-cream sundae and talk to your AI girlfriend.)