If you do a google search for "annex haiti", you get a bunch of calls for the US to annex Haiti. It seems like everyone's asking "What's the US to do?". However, the US shouldn't do anything but help the Dominican Republic help Haiti.
The Dominican Republic shares the same island and has working facilities and has a recent history of running a country relatively well. Let the DR build roads and infrastructure in exchange for taking over the tax administration of Haiti. The DR benefits economically and removes a source of instability on the island, Haitians get local administration and a long-term committed partner for growth.