Invading ukraine. According to nato and many others. And this has been the worst week of the worst Ebola Outbreak ever. U. S. Health officials preparing to test a vaccine in the United States as we witness the biggest weekly jump in cases yet. Good afternoon, everyone. Welcome to the lead. Im jake tapper. We begin of course, with the world lead. 35 million americans will be traveling this labor day weekend, according to aaa. Thats the highest number in six years. So pack the kids in the car or board your flight or take your seat on the train. Dont worry too much about terrorists from isis committing an atrosity on u. S. Soil according to the fbi and department of Homeland Security who are, they say, unaware of any specific credible threat to the United States homeland from isis. This is despite the British Government raising the alarm about isis within its own borders. Lets get to our pentagon correspondent barbara starr. What exactly are the british saying . This is the issue on this