Under new rules adopted by the Obama administration last year, deportation will now be reserved for undocumented felons, national security risks or repeat immigration offenders. Undocumented immigrants guilty of only minor legal violations and who have long and substantial ties in the United States would have their deportation cases set aside. The policy shift addresses one of the major concerns of the U.S. bishops. They have long argued that immigrant families should not be broken up over small offenses. The change is “a potential seismic shift in enforcement,” said Geoffrey Scowcroft, an attorney who manages immigration legal services for Catholic Charities in Oregon. “We are in the very early stages of this, but this policy is as close to good news as we have seen in years,” he said. The Department of Homeland Security described the new discretion as a way to unclog immigration courts, which are now backlogged with more than 300,000 cases.