The reasons for the slower response –– after San Bernardino versus Paris–– are both practical and political, according to security experts and sources on Capitol Hill.

For one thing, Congress’s response to the Paris attacks was approved after the Dec. 2 shootings in California. That timeline helped create the public perception that lawmakers were responding to both attacks in one swoop, despite the fact that the visa waiver bill addressed issues starkly different from the visa concerns at the heart of the San Bernardino case.

Matt Mayer, a national security expert at the American Enterprise Institute, said Congress has a tendency to adopt a “one-action-covers-the-bases” strategy, even if subsequent events might raise new questions and expose new vulnerabilities.

“Congress’s mentality is: We acted,” Mayer said.