election law - constitutional ambiguity?

[🐒Gods of Prosperity🔱🐲💸]

This is the Tenth Amendment according to the Wiki. I'm finding it a bit ambiguous.

"In order to vote or be a candidate in an election, a person must have been a registered voter on the tenth day before that election. If a voter changes their state of registration in the ten days before the election, the state from which they were originally registered shall be the state from which their vote is cast."

Since elections last more than one day, what are we talking about here? Ten days before the beginning or the end? Exclusive or inclusive of the final day? Are time zones relevant here or only 24 hour periods?

For example, to vote in the upcoming federal elections, someone must have been registered by exactly when?