The Bush tax cuts for the wealthy and top earners that was enacted in 2010 would greatly reduce the deficit for our federal government, as this would allow more tax revenue to flow into our budget. This would have to be congruent with the current budget cuts we are currently seeing to continually lower the budget over time.
Although allowing the tax cuts for the wealthy to expire would have a small impact on the deficit, it would not be large enough to noticeably cut the deficit. First, the tax cuts in question only affect a very small amount of people. Second, most of those people still will not end up paying the taxes in question because they have accountants who are very skilled at hiding money in offshore accounts in order to make it look like they earn less than they actually do.