Immigration offenses account for more than half of the federal criminal caseload, according to data compiled by the Transactional Records Access Clearinghouse database, with illegal entry and re-entry cases accounting for the lion’s share.The possibility of adding thousands of new inmates to federal prisons on decade-long sentences would have a massive impact on the Bureau of Prisons, whose total inmate population stands at approximately 155,000.“The cascading effects of subjecting thousands of individuals to a 10-year mandatory minimum sentence cannot be overstated,” reads a letter to congressional leaders penned by the Federal Public and Community Defenders Legislative Committee. “The entire system would be driven by the demands of section 1326 [illegal re-entry] cases, at the expense of violent crimes and other offenses that pose a far greater threat to public safety.”Criminal justice and legal groups also warn that the bill could paralyze the federal courts. Nearly all illegal entry and re-entry cases are convicted through plea deals with reduced sentences in order to shuttle them quickly through the system.But it wouldn’t make sense to plead guilty to a crime carrying a 10-year mandatory prison sentence.“If this passed, the federal courts would implode,’’ said Kara Hartzler, an attorney with Federal Defenders of San Diego.