Obama legacy: Handing Trump a broad view of war powers

In his final weeks in office, Obama has broadened the legal scope of the war on extremism, the White House confirmed Monday, as it acknowledged for the first that the administration now asserts it is legally justified to take on the extremist group al-Shabab in Somalia.

White House counsel Neil Eggleston called the report — the first of its kind — a demonstration of how Obama has ensured "that all U.S. national security operations are conducted within a legal and policy framework that is lawful, effective and consistent with our national interests and values."

For Obama, the heavy reliance on 9/11-era authorities is a powerful illustration of how his campaign pledges to construct limits on the president's war-making powers were confounded by difficulties of dealing with Congress and the pressures of rapidly evolving threats.

In the first days of his presidency, he signed executive orders prohibiting secret CIA "black site" prisons and ending harsh interrogation techniques considered by many to be torture.

Wary of major overseas entanglements, he turned increasingly to surgical, stealthy operations like drone strikes that have traditionally operated under a murky legal framework.

In 2013, he notably pulled back from impending U.S. airstrikes in Syria, and instead sought formal approval from Congress that never materialized.

[...] under pressure from civil liberties advocates, he put in place tougher rules for drone strikes, aiming to limit civilian casualties.

Some of those details are outlined in the 61-page White House report, the most comprehensive explanation to date of the policies the Obama administration has applied for drone strikes, detention of terrorists and access by humanitarian groups like the International Committee of the Red Cross.