Here’s a way to deal with this.
Pass the bill, but only after amending it so that the determination of whether a state has engaged in a pattern of racial discrimination is made by Act of Congress.
Let the Congress hold open, public hearings where both sides get to make their case openly, publicly and transparently.
You’ll see the Dems falling all over themselves voting against it.
The test involved registration or participation of less than 50% of the voting age population....but surely, Census Bureau estimates of who is and who is not a citizen are very suspect compared to what it was in the 1960’s. I don’t think any statistical test is logically possible. Legally is another story.