MARGARET WARNER:

This week in Brussels, NATO's defense ministers will discuss setting up outposts along its eastern front to do just that. But is this wise or necessary?

Evelyn Farkas just left her post as assistant secretary of defense for Russia, Ukraine and Eurasia.

EVELYN FARKAS, Former Deputy Assistant Secretary of Defense: This is something that we absolutely need to do. It is a sign of our resolve. It's a sign that the United States is there with our NATO allies, that we're there also to send a signal to Russia. I mean, it's clearly a deterrent effort.