Sen. Mark Udall, D-Colo. Sen. Mark Udall, D-Colo. (AP | Susan
Walsh)  WASHINGTON — Sen. Mark Udall said he was frustrated
Thursday that he did not get substantive time — and staff
expertise — with classified documents that lay out a legal
rationale for drone strikes against Americans working with al-
Qaeda abroad.  President Barack Obama released a confidential
legal opinion to senators on the Intelligence Committee on
Thursday — in part because Udall, a Colorado Democrat, and Sen
Ron Wyden of Oregon pushed aggressively for transparency on the
government's constitutional justification to kill American-born
citizens abroad in counterterrorism operations.  But the
senators on Thursday were not allowed to bring in staffers or
their own lawyers to help them parse the legal language, Udall
said. He said he had only 15 to 20 minutes with the complex
legal opinion early in the morning because his day was so packed
with other obligations.  "The restrictions on what I can say or
what I can't say are frustrating," Udall