The Trump administration and Congress will host a flurry of NATO events this week, timed to the alliance's 70th anniversary.

Why it matters: The past couple of years have been tough for NATO, with Europeans still struggling to pull their own weight on defense spending and warily watching President Trump to see if he’ll pull the plug on the alliance. Although such concerns can be overcranked — the U.S. military is doing more in Europe than it was two years ago — the alliance is still strained by unpredictable disruptions from its largest and most important member.

Details: NATO Secretary General Jens Stoltenberg will visit President Trump Tuesday and then address a joint session of Congress. Also this week, Vice President Mike Pence will join NATO foreign ministers and experts at a policy conference, and Secretary Mike Pompeo will host all 29 NATO foreign ministers at the State Department.