Dave Roberts has written the definitive piece on why Democrats should make the next stimulus package conditional on a non-negotionable demand that it include funds for universal access to postage-paid mail-in ballots. Read the piece but in a nutshell... https://www.vox.com/science-and-health/2020/4/8/21209306/election-2020-vote-by-mail-wisconsin

his argument is that, first in foremost, given that the coronavirus good well last into November, there is no other way to guarantee a free and fair elections

Second, while Trump and the GOP have already started the drum beat that vote by mail will lead to massive fraud etc., it is simply, profoundly not true

Third, while Trump and the GOP are arguing that vote by mail will it vantage of the Democrats, that also is not true according to every substantive study that’s been done

Fourth, while it is certainly the case that millions of American voters will believe anything Trump says, there is a vast part of the electorate that is persuadable on this issue—and I would add, the basic human desire not to die while voting works against the Trump argument

And finally, while Democrats in Congress will feel pressure to pass a stimulus bill quickly, they should recognize that Trump and the GOP need the stimulus more than than Democrats do because

There is a shit ton of political science showing that the party in power is the one voters blame when things go wrong. Perhaps that will be different this time, but...

Democrats should nevertheless have the courage to stick to their guns on this one, because absent free and fair elections in November their chance of victory is zilch. Plus, it is absolutely the right and principled thing to do.