Three sold-out Taylor Swift concerts were canceled in Vienna earlier this week after authorities learned of potential violent attacks planned for Thursday or Friday. Tracy Walder, a former CIA officer and NewsNation national security contributor, discusses Swift can't perform in Vienna as the "abstract" threat continues. Walder says if the concert wasn't canceled, it could have been " catastrophic." #Austria #terror #TaylorSwift Start your day with "Morning in America," NewsNation's live three-hour national morning newscast hosted by Markie Martin. Weekdays starting at 6a/5C. #MorningInAmerica NewsNation is your source for fact-based, unbiased news for all America. More from NewsNation: newsnationnow.com Get our app: trib.al/TBXgYpp Find us on cable: trib.al/YDOpGyG How to watch on TV or streaming: trib.al/Vu0Ikij