Every politician knows what to do but none of them will do it because we as a society use tax to change the way people behave. We finance things like stadiums with sin tax and raise the sin tax so people don't sin anymore and wonder why revenue is falling.
Every time we cut taxes like income and capital gains the revenue to the treasury increases. It works every time. It worked when Kennedy did it in 61, it worked when Regan did it and it worked when Bush/Clinton did it. Then you get congress that sees all the money come into the treasury and they spend spend. Than they think about raising taxes so they can spend some more and the economy goes down the toilet.
To cut the deficit we must cut taxes and cut spending.