The movement's problem is not in persuading people to support tax increases, but in gaining support for spending. The Federal government and states are swimming in surpluses right now. If we can't sell new spending initiatives now, why should we be able to sell tax increases?
Problems in the way spending is motivated is a long discussion. One problem is that the content of such appeals often derives from the work of advocacy groups in D.C. who lobby Congress. These groups are each so focused on their own corner that their appeals tend to be narrow, sentimentalist, and lacking in intellectual heft. (Exhibit A: "Stand for Children"). Their appeals mirror the views of their sponsors, rather than of those who need to be convinced.
Of course, a major problem is the disconnect between public opinion of any sort and what motivates members of Congress. Congress is very aware of what the public wants, but it is not constrained to act on these wishes, given the firewalls of money and party organization.
The tax debate right now is to my way of thinking very much a tertiary priority.
mbs