The original immigration reform bill would prevent people in the US illegally from being deported if they have applied for provisional legal status. Senator Sessions, so far the most vociferous critic of the bipartisan reform package, would nix that, allowing people to be deported while they have an immigration claim pending.
Moreover, the Sessions amendment would not allow people who have been deported or who left the US of their own volition to apply for provisional legal status, even if they are otherwise eligible. The original bill allows such individuals to apply, to the relief of immigration advocates who have been unhappy about historically high deportation levels during President Obama’s first term.