The founding of America was not "leftist" it was liberal in the true definition (for limited central authority, personal responsibility and amenable to NECESSARY change - not change for its own sake). Actually Left and Right doesn't truly describe the political spectrum - Google for the "Nolan chart".
. Of course, since the socialists (massive central authority, little to no individual responsibility (only to follow the dictates of authority to the letter), couldn't succeed under their true name, they have tried everything to hide their nature - hijacked the name "liberal" (a sobriquet they now reject since they have polluted it so badly) and now are trying to hide behind "progressive", which is beginning to fail them as well. I wish we could get back to using words as if they meant something but when the meaning of is can be debated... Using words properly, Rush should be called a reactionary liberal (wishes to revert (change) to some previous state of affairs) not a conservative (which wishes to preserve the current state of affairs, ugh!).
. Actually you should try reading some Sowell (The Vision of the Anointed, and Basic Economics would be a good start), so you can understand from whence his comments arise. As a callow youth, he was full throttle socialist, now I would describe him as small govt libertarian - a label he rejects. Sowell is, if not the greatest extant thinker/writer on the social condition, then very near to it.
. Just to help you with that quote: leftist to him means socialist, big govt, limited individual liberty/responsibility - and that those types flourish in academe, govt bureaucracies (actually any b'cy) labor unions, environmentalist facades for anticapitalist wackos (e.g. Earth First, PETA, etc.).
.bh.