Ro Khanna is the first elected official who is saying that if absentee ballots don't go out early, if polling places are restricted, then Biden can't win some of these states (held by GOP Governors or State Legislatures) by a margin comfortable enough to avoid these states disputing the results. Then they'll throw it to the House of Representatives where Biden would surely lose the election.
This would mean states like Florida, North Carolina, Arizona and Wisconsin (has a gerrymandered GOP legislature).