Both parties have been promoting neoconservatism and neoliberalism. For the first, the government and the media tell the public that other countries are being oppressed and must be freed, and the U.S. is the best country in the world to help them become free by various (legal) means. Secretly, they do so in order to justify military spending (otherwise, the public will wonder why so much money is being spent on the military), to access natural resources like oil and minerals, and to gain strategic advantages over military rivals, and that includes various (illegal) means like supporting coups and various regimes, financing armed groups (including terrorists), bribing officials, and so on.
Together with that is neoliberalism, or the belief that only liberal democracies and free markets work. Policies include deregulating at home so that Wall Street and financiers can engage in more speculation, and policies that entice or even force other countries to open up their economies for exploitation and to remain dependent on the U.S., especially on the dollar as a reserve currency. These include structural adjustment and financial aid with strings attached: countries need to increase taxes, decrease public spending, allow for democratic elections (but only politicians who favor the U.S.), allow for more importation and the entry of more powerful businesses, and so on.
Both parties have been employing one or the other since the early part of the previous century, and both since Reagan.
One main reason behind both is the use of the dollar as a global reserve currency, something which made many things that the U.S. could buy abroad cheap but also made many things that the U.S. could sell to others in order to earn expensive.
That’s why sometime after 1961, economic growth slowed down, except for one high in 1984. Also, trade deficits started to take place after 1971. And then borrowing and spending levels started growing considerably after 1981.
From there, the U.S. has been in a borrowing and spending spree since, with oligarchs encouraged to engage in more speculative activities and get-rich schemes quickly, and credit created used to pay for a very expensive military needed to coerce other countries to remain dependent on the dollar.
That’s why the CNN only reported once about Saddam using the euro for oil trade, which might have been the real reason why the U.S. attacked Iraq a year later. The same goes for Libya’s attempt in opening an oil bourse, and how Iran was threatened by the U.S. after it did similar, with even Japan scolded by the U.S. for buying oil from it.
Meanwhile, the public, regardless of whether they supported Democrats or Republicans, said little about both ideologies, except that the U.S. is special (it’s part of exceptionalism) and others (from China to Iran to Russia to anyone else who criticizes the U.S.) should be taught a lesson, at least for the last few decades.
That’s why there have been no nationwide and prolonged protests since the Vietnam war, even though similar suffering and destruction took place in Iraq, Afghanistan, and elsewhere, and involving both parties.