Every carrier has a way to report text messages as SPAM.
For example, to report SPAM on T-Mobile, forward the offending text to 7726 (which spells SPAM). They will reply that they will take care of it. And they will.
The carriers are very likely to flag similar messages in the future (including ones to be sent over the next several days) and block them from coming through.
Most of these senders will never have any clue as to whether their text messages are getting through, so your SPAM reporting will have even more of an impact because they will have more difficulty changing their content or strategy.
It may also be possible to join a class action suit against some of the text spammers, but this may not have an immediate impact on their role in the current election.
Thanks for the tip!