In 2004, Arizona passed a law requiring voters to provide proof of citizenship to vote

Prop 200, the 2004 Arizona law that started all this trouble, was pushed hard by republicans and in particular promoted by the Federation for American Immigration Reform.

The Federation for American Immigration Reform (FAIR) is a nonprofit, anti-immigration organizationThe Federation for American Immigration Reform (FAIR) is a nonprofit, anti-immigration organization in the United States. The Southern Poverty Law Center classifies FAIR as a HATE GROUP with ties to WHITE SUPREMACIST groups. FAIR was founded in 1979 by Michigan surgeon and white nationalist John Tanton.[13][14][15] https://en.m.wikipedia.org/wiki/Federation_for_American_Immigration_Reform

So the strange story here is that republicans and white nationalists, in an effort to stop nonwhite people from voting, created this situation in which a large number of white republicans are in fact ineligible to vote, and have been voting illegally for years.

Now that democrats have discovered this issue, white nationalist republicans are trying to blame democrats for the problem that white nationalist republicans created.