I have a friend who holds a passport that would normally enable them to get an ESTA to enter the US. I frequently travel there on reasonably short notice and they would like to accompany me some time. Last time we tried this the ESTA process timed out (neither accepted nor denied), which we believe to be due to their travel to Iraq (properly declared, and for entirely non-problematic reasons). I thus believe they will need a visa.
For an ESTA, you have to supply dates of travel, and this works for short notice trips as the ESTA process takes a couple of days. But for a visa you appear to need to supply dates of travel ahead of time, and (perhaps?) show evidence. How can one get a visa for "trips unknown in the future"? Does one have to eg book a refundable plane ticket, apply, and get a refund? What's the best way to proceed here.