The Constitution meant for tax collected to be spent for the needs of the nation. Army, Navy, Post Office, Judicial System, war supplies, government buildings and obligations, etc.
It was not intended that taxation be used for social engineering.
BO’s talk about taxing taxing and building roads to make work would be legal under the Constitution, as much as it sounds like the WPA and as much as it is wrong because it does not build our industrial and commercial base, but it is not in a strict sense social engineering even though we can see that it is intended to be so.
Bribery to get votes is a pretty poor and obviously unconstitutional reason for taxation.
Is that why Barney Fwank talks funny - it's McCain's fault?