(CNN) - A foolproof system for staving off terrorist attacks couldn't exist in an open democratic society, two lawmakers said Sunday.
Speaking on CNN's "State of the Union," Sen. Dan Coats, R-Indiana, and Rep. Adam Schiff, D-California, agreed that while more robust intelligence-sharing should have taken place in the lead-up to the Boston Marathon bombings, the amount of surveillance required to protect fully against more violence could never exist in a democratic society.
"We're doing everything we can, but we have to be right 100% of the time. And they only have to be right 1%," said Coats, who sits on the Senate Select Committee on Intelligence.
Schiff, a member of the House intelligence panel, concurred.
"I think we might do a disservice to the American people if we suggest that there's always got to be a problem when anything bad happens," he told CNN chief political correspondent Candy Crowley. "The reality is we would need to take such intrusive steps, and make this country into a police state that no one would want to accept in order to completely prevent these low-tech attacks."
The discussion came after allegations of an intelligence failure in the years leading up to the Boston attack, which left three people dead and hundreds injured. Some lawmakers, mostly Republicans, have said a lack of informational sharing between intelligence agencies led one of the suspected perpetrators, Tameran Tsarnaev, to fall through the cracks. While he was identified as being potentially radicalized in 2011 by Russian authorities, who notified the FBI, he was cleared after questioning. He was, however, added to three federal terror databases.
Lawmakers contend an opportunity was missed when Tsarnaev traveled to Russia for six months in January 2012. His travel generated a notification to American intelligence, but no action was taken to determine how the trip affected Tsarnaev, who died last week after a confrontation with police.
"Somebody sitting somewhere could have said, you know, that name's familiar. I think we did a file on that. Let me check into that," Coats said Sunday.
Schiff argued for better cooperation with Russian intelligence, which he alleged was still withholding information from American officials. He cited the news, revealed Saturday, that Russia had intercepted a communication between the mother of the accused Boston Marathon bombers and someone who may have been one of her sons "discussing jihad" in 2011.
"There's got to be a basis for why they went up on her electronically or why they went up on one of her affiliates or associates," Schiff said. "We don't know that. We haven't received that information from the Russians. I think they do know more than they’re telling us."
The two lawmakers deviated on the issue of issuing Miranda rights to the surviving Boston bombing suspect. The warnings, which advise criminal suspects of their constitutional rights against self-incrimination, were first administered while a magistrate judge presided over a hearing in Dzhokhar Tsarnaev’s hospital room.
Tsarnaev was not immediately apprised of those rights after his capture late April 19 under what is called the "public safety" exception. The exception allows for limited questioning by law enforcement of a suspect to determine if there is imminent danger to the public of attack.
After being read his rights, Tsarnaev has since not answered "substantive" questions from investigators, officials have told CNN.
Coats argued that exception should have been prolonged to gather more information from the suspect.
“I was very surprised that they moved as quickly as they did,” he said. “We had, I think, legal reasons and follow-up investigative reasons to drag this out a little bit longer. We could have done that.”
But Schiff alleged that holding off any longer would have been harmful to Tsarnaev’s eventual prosecution since the statements he made before being read his rights could be legally challenged.
“Already I think the statements that the suspect made are going to be challenged by the defense team,” he said. “And while the priority has to be on making use of any information that could protect the public, it's also valuable to be able to admit those into evidence.”
CNN’s Bill Mears contributed to this report.