likely successor. a former senior u.s. military official told cbs news that while the leadership has changed, al qaeda remains a resilient adversary that seeks out safe havens. john. dickerson: a resilient adversary. thank you, catherine herridge. after nearly a week of delays, outrage and proifts, tonight the senate is once again trying to pass a bill which will expand healthcare and disability benefits to veterans exposed to toxic burn pits in iraq and afghanistan. cbs scott macfarlane has the latest. reporter: with war veterans outside the capitol demanding action, a long-awaited plan to expand medical benefits for service members headed towards passage, making it easier for vets sickened by toxic fumes to get treatment. susan zeier s son-in-law died from lung cancer, she believes from exposure to burn pits in iraq. the first words out of the oncologist house was what the hell have you been exposed to. reporter: veterans felt blindsided last week when