I am not defending Cantor's two-faced actions but the big DENIED stamp on this Enlist Act was more a consequence of the pressure anti-immigrant groups placed on Cantor, even starting funding campaigns for his tea party opponent and letters/faxes/emails fervently vowing to do anything possible to get him out of office based on activity I've seen on Twitter and conservative forums.

Do notice that his congressional district is 74% white, in the suburbs, and during Cantor's last primary challenge (by a Green party candidate nonetheless!), he received his lowest vote percentage since taking the hill in 2000.

tl;dr He's scared of losing his job and there's nothing in it for him if he agrees to Enlist Act.