A group run by supporters of Senator Marco Rubio sent a mailing to Iowa Republicans this week criticizing Senator Ted Cruz for not condemning Edward J. Snowden, the former National Security Agency contractor who leaked a trove of classified documents.

Linking Mr. Cruz to Senators Rand Paul and Bernie Sanders, the group, the Conservative Solutions Project, placed pictures of the three presidential candidates side by side.

“These senators have defended Snowden’s actions,” the mailer reads, citing quotations from each of the three about Mr. Snowden. The mailing was shared by an Iowa Republican, who requested anonymity because he does not want to appear to be taking sides in the campaign.

Mr. Cruz in the past has offered some conditional words of praise for Mr. Snowden for exposing government surveillance. But he has also said, “If Mr. Snowden has violated the laws of this country, there are consequences to violating laws and that is something he has publicly stated he understands and I think the law needs to be enforced.”