- John Thune: Brussels attacks are a reminder the United States must confront threat ISIS poses to nation's transportation system
- Ensuring dangerous individuals can be barred from working in secure areas of airports should be no-brainer, he says
John Thune, Republican, is a U.S. senator for South Dakota. The views expressed are his own.
(CNN)Last month, 35 innocent people, including four Americans, lost their lives when ISIS attacked a subway station and airport terminal in Brussels. This was just the latest in a string of attacks ISIS has orchestrated or inspired against Western targets over the past two years -- attacks that have killed more than 650 people.