Cruz is probably the highest ranking Constitutional expert in all this. Let's see what happens. Not sure a sitting Senator can wear this hat.
Doesn’t affect his state specifically so not sure why he wouldn’t be able to. The question is to the constitutionality of the Pennsylvania court ruling. President, if it gets to Congress, is chosen by the house.
Of course Senators can argue a case if he is a lawyer. Ted Cruz graduates from Harvard Law school. After law school, Cruz worked as a law clerk for several judges, including Supreme Court Justice William Rehnquist from 1996 to 1997.
After a stint as associate deputy attorney general at the Department of Justice, Cruz became director of the Office of Policy Planning at the Federal Trade Commission in July 2001. His time at the FTC was marked by successful defeats of collective bargaining proposals between physicians and healthcare programs, as well as legislation that aimed to curb below-cost gasoline sales.
In 2003, Cruz became the solicitor general of Texas. He argued a total of eight cases before the U.S. Supreme Court during his five years in the post, his victories including a case from 2008 in which he advocated for the preservation of the death penalty for a Mexican citizen convicted of raping and murdering two teenage girls.
Cruz would do well arguing this case.
John Quincy Adams did as a sitting member of the House of Representatives in the Amistad case. That's a precedence.