WASHINGTON, July 6 (UPI) -- Experts see cracks in Congress' plan to improve security by requiring passports for all U.S. citizens re-entering the country.

The huge backlog of passport applications spurred by the first phase of the Western Hemisphere Travel Initiative means adjudicators don't have enough time to thoroughly check each application, The Christian Science Monitor reported Friday.

Colin Walle, the president of the union that represents adjudicators, says on average they have just 2 1/2 minutes to evaluate an applicant's eligibility for a passport.

The task could be accomplished in a short amount of time if the databases used to verify an applicant's identity and eligibility weren't incomplete.

David Heyman of the Washington-based Center for Strategic and International Studies says people who shouldn't get passports may continue to slip through the cracks in the absence of improved information-sharing.

Heyman says many links between government agencies haven't been tested or fully established.

A State Department spokesperson says work is constantly being done to expand the amount of information used in the adjudication process.