In the fight for mail-in voting, we just gained a foot.

When the Republican Party wanted to challenge state laws that count ballots postmarked by Election Day but received afterward, it explained its reasoning in plain terms: "Democratic voters tend to mail their ballots later on average than Republican voters, which results in late-arriving ballots favoring Democratic candidates."

That admission tells you almost everything you need to know about the modern GOP's approach to elections. Over the last decade, Republicans have understood that close elections are decided as much by which votes count as by who voters prefer. They have prioritized gaining every advantage in election rules that they can find, no matter how small.

Like a sprinter seeking an edge from lighter shoes or more aerodynamic clothing, Republicans understand that the results of elections are measured in inches, not yards or feet.

They know that a single tweak to voting rules can be the difference between winning an individual race and controlling Congress. And so, for years, the party has waged a quiet but relentless legal campaign to reshape the rules governing how ballots are cast, counted and thrown out, always with an eye toward the margins.

As a lawyer, I have spent countless hours litigating to stop Republicans from gaining an advantage by disenfranchising voters. No issue has dominated the voting rights landscape over the last six years more than mail-in voting, and specifically, how mail-in ballots are accepted or rejected.

I have fought with Republicans over the procedures and standards for matching signatures on return envelopes. I have litigated whether ballots with missing dates should be rejected or counted. In both instances, we have won more often than we have lost.

The result has benefited voters and, by extension, democracy itself. These fights rarely make headlines in the legacy media, but they determine whether a ballot cast by an eligible voter ultimately counts.

In recent years, no issue has been a higher priority for Republicans than the question of so-called late-arriving ballots: Ballots postmarked on or before Election Day but received by election officials afterward.

The GOP has spent millions arguing in court that counting these ballots violates federal law. And my law firm has fought them every step of the way...