They can do it without taxes going up. Get some private financing (Larry G., Travlers, The Hartford, UTC, Aetna), some state funding, Hartford has to put in some cash, have an arena surcharge on all tickets, naming rights. With the right mix it wouldn't be that tough to swallow.
People will look at Hartford and say there are other issues the money would be better spent; mass transit, schools, police. Well those areas are improving and there is money behind those initiatives. The police department has hired new officers, there is a new public safety compound being built, there is the New Britain Busway and New Haven-Springfield Commuter rail both fully funded and getting closer to construction. Schools are being built and renovated. The new superintendent is making sweeping changes. We'll have a new national park, an entertainment district next to the newly opened science center. An arena kinda completes the deal. If Hartford can get that you won't recognize it ten years from now.