Political txt, email and calls are (mostly)protected by the first amendment as free speech. It would be unconstitutional for the government to restrict it with very limited exceptions, mostly related to imminent threats of violence.

Commercial speech can be regulated provided certain requirements are met that are more widely applicable, a four part test is used. See Central Hudson Gas & Electric Corp. v. Public Service Commission. Also under Zauderer v. Office of Disciplinary Counsel the government can compel commercial speech, require advertisers to include factual disclaimers.

So laws like the CAN-SPAM act prohibit unsolicited commercial advertising via txt or email if certain requirements are not met.