I am a Russian citizen living in EU. I generally avoid trips to US. BTW, me and some of my colleagues, postdocs or PhD students, had to go through the infamous TAL (technology alert list) checks. What it practically means: 1) you are a citizen of some US "enemy" country, like xUSSR, China, Brazil or, God forbid, Iran 2) you have a PhD in any engineering discipline (true for architects, computer scientists, chemists, physicists, etc) or you work towards your PhD 3) you are going to a conference in US Then they will do a mock background check for long enough to grant you a visa one day after the conference ends.