We need a real financial transaction tax, not the silly 0.003% that currently exists. Something like 0.25%/0.25%, forward/swap would bring in around $140 billion in revenue. Another raise in capital gains for those making over 400k/450k to 25% (actually, 28.8% when you factor in new Medicare surtax) and 20% for everyone else; another $110 billion in revenue.
Ther are a few other, simple ways to raise revenue. Legalise marihuana, tax it like alcohol and tobacco. Annual revenue might increase by some
20 bn USD.
Fuel taxes: Current US fuel retail prices are somewhere around 1 USD / litre, while most European states have prices above 1.50 / litre, without facing poverty and starvation. Annual gas consumption in the US is around 140 bn gallons. Introduce a 50 ct/gallon fuel tax (of course, gradually, with pre-announcement, so motorists can in advance switch to low-consumption models). Fuel prices will still be far below European levels, but there is some 50-70 bn. additional revenue (depending on the consumption reduction triggered by the tax). Positive side effects: COČ reduction, innovation pull and demand boost for the car industry, increased competitiveness against imports (which become more costly to be transported), and possibly quite some re-location of manufacturing from China and Mexico back into the US.