Barr has said he looked to that opinion in concluding that Trump did not illegally obstruct the Russia probe, which was an investigation of whether his campaign had colluded with Russia to tip the 2016 election. The Justice Department turned over other documents to Citizens for Responsibility and Ethics in Washington as part of the group's lawsuit, but declined to give it the memo. Government lawyers said they were entitled under public records law to withhold the memo because it reflected internal deliberations among lawyers before any formal decision had been reached on what Mueller's evidence showed. But U.S. District Judge Amy Berman Jackson said last year that those arguments were disingenuous because the memo was prepared for Barr at about the same time as a separate Justice Department letter informing Congress and the public that Barr and other senior department leaders concluded that Trump had not obstructed justice.