The risk of an attack against the US with weapons of mass destruction is growing, and it shouldn’t surprise anyone. Except maybe some Obama voters.

The odds that terrorists will soon strike a major city with weapons of mass destruction are now better than even, a bipartisan congressionally mandated task force concludes in a draft study that warns of growing threats from rogue states, nuclear smuggling networks and the spread of atomic know-how in the developing world.

The sobering assessment of such threats, due for release as early as today, singled out Pakistan as a grave concern because of its terrorist networks, history of instability and arsenal of several dozen nuclear warheads. The report urged the incoming Obama administration to take “decisive action” to reduce the likelihood of a devastating attack.

“No mission could be timelier,” says the draft report of the Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism, which spent six months preparing an assessment for Congress and the new president-elect. It adds: “In our judgment, America’s margin of safety is shrinking, not growing.”

The report, ordered by Congress last year, concludes that terrorists are more likely to obtain materials for a biological attack than to buy or steal nuclear weapons. But it says the nuclear threat is growing rapidly, in part because of the increasing global supply of nuclear material and technology.