I'm not a lawyer, but...
I believe he could, but I think his working the pardon angle has been a better use of his time. He has objected to issues other than legal ones, for the most part.
Another group has covered the legal issues pretty well--it's probably best to not muddy the water with peripheral issues (IMO). Here is a cut and paste from the amicus brief filed on May 24, 2007. That's a pretty good line-up and the arguments are even better. :-)
BRIEF AMICUS CURIAE OF
CONGRESSMAN WALTER B. JONES,
CONGRESSMAN VIRGIL H. GOODE, JR.,
CONGRESSMAN TED POE,
GUN OWNERS FOUNDATION,
U.S. BORDER CONTROL FOUNDATION,
U.S. BORDER CONTROL, AND
CONSERVATIVE LEGAL DEFENSE AND EDUCATION FUND
IN SUPPORT OF APPELLANTS
I was thinking that having high-profile individuals (like congressmen)filing "friend of the court" briefs couldn't hurt and might help.
My question is answered...
I love Duncan Hunter and his diligence in getting freedom for Ramos and Compean. I truely hope that if Hunter does not gain in the polls and win the nomination that he is chosen for VP or to head up the department of homeland security in the next administration. Then he would be in line with great recognition to become President in 2016. I believe he and Fred are the best! If they were even in the polls I would be going nuts trying to choose between them!