“[C]ivil libertarians and even experienced FBI interrogators argue,” Serwer writes, “that attempting to modify Miranda would be a political solution to a national security problem that doesn't exist.”
Conservative criticism of Miranda itself has had a dramatic effect, which can be seen in the administration's handling of the Times Square attempt. Testifying before a Senate subcommittee on May 6, Holder said Shahzad had been questioned for "hours" under the public-safety exception before being read his Miranda rights. According to the administration, he also waived his right to be brought before a judge and so was questioned for two weeks before seeing the inside of a court on Tuesday.
After Holder announced the administration sought to change the rules around Miranda, The New York Times reported that the administration also wanted to be able to prolong the time that law enforcement can detain a suspect before bringing him or her before a judge, generally 72 hours. Under the PATRIOT Act, law enforcement can actually get an extension -- in the case of a non-citizen -- as long as seven days. The administration's position on Miranda represents a reversal from its previous position, supported by veteran FBI national security officials like Ali Soufan, Jack Cloonan, and Joe Navarro, that law-enforcement procedures don't interfere with intelligence gathering.
Serwer’s full piece  is worth a read.
This week, People For joined 34 other progressive organizations in sending a letter  to Holder urging him to reconsider the proposed move. “Weakening Miranda,” the groups wrote, “would undercut our fundamental Fifth Amendment rights for no perceptible gain.”