I am a Syrian citizen. I want to visit my brother in the United States. Can I travel there with an existing, valid B1/B2 visa in my Syrian passport, after latest travel ban Presidential Proclamation of December 4, 2017?
The proclamation does not revoke any visas that were issued before the effective date of the proclamation, and the restrictions in the proclamation do not apply to any foreigners who had a valid visa on the effective date of the proclamation for that person. (And if you got your visa after the effective date, that would mean you must have gotten a waiver, so the proclamation also does not restrict you.) So if you have a valid visa, you should be able to travel to the US.