A number of senators are considering amendments that would bolster the electronic employment-verification system known as E-Verify. The moves could help appease Republicans looking for stronger border-security measures. But they also may set off Democrats, who fear rushing the implementation process or stepping on human rights.

The issue trails the feistier debates of legalization and guest workers, but it has sparked attention because lawmakers consider E-Verify a critical benchmark before undocumented residents can gain citizenship. And a myriad of contradictory concerns about the revamped system — from targeting identify theft to fears of a national ID database — ensure debate next week when the Senate takes up the bill.

“It’s a bargaining chip,” said Jessica Vaughan, the director of policy studies for the Center for Immigration Studies. “Both sides are looking to peel off votes here and there.”…

“Even the E-Verify, which I thought was going to be — they claimed would be — really good, I’m very uneasy about a whole new system and putting it off for several years,” Senate Judiciary Committee member Jeff Sessions (R-Ala.) told reporters.