concerning to u.s. law enforcement agencies. >> reporter: the mexican government announced it is tightening the flow of intelligence and still evaluating whether a u.s.-backed program to use polygraph testing to root out corrupt mexican security officials will continue. president obama says he's keeping an open mind. >> i'm not going to yet judge how this will alter the relationship between the united states and mexico until i hear directly from them to see what exactly are they trying to accomplish. >> reporter: a recent poll shows mexicans overwhelmingly welcome u.s. involvement in fighting the drug war. 55% approve giving them money and weapons. but the president's institutional revolutionary party has historically been suspicious of outside influence and fiercely protects its sovereignty. >> ultimately, the president is going to be accountable to the mexican people as to how that -- how his policies will quell or