First, I am not sure, and this question makes remarkably little effort to clarify, what "optimization" means in this context. But I will hazard a guess that it is unlikely that Chomsky's opinion on that matter would be shared by more than a quite small part of the US electorate. More on Mearsheimer at end.
Second, there are a number of theories in international relations about what motivates states: realism, constructivism and liberalism for example. While it's not the purpose of this answer to go into them ( Constructivism's wikipedia writeup is a shining example of impenetrable jargon, with nary a concrete example), it seems clear that all indicate a certain inertia in how a state relates to any given other state. So... once arrived at, FP would continue more or less in the same direction.
OK, now let's get on to the bones of the question. Here are some groups I can think of (I'll concentrate on early 2000s Bush administration for examples):
Obviously, the president's worldview has a huge input. But many POTUS are not internationally minded by nature and experience until they get the job (anyone remember Sarah Palin's coastal FP experience?).
Or Obama being unsure about how to proceed in Afghanistan early in his career (to +40000 troops or not to 40000+ troops?) and thus relying on his advisors.
At the same time, POTUS's do have primary responsibility for high-level FP and their frequent lack of expertise going into the job can yield thing like Trump ditching the JCPOA or Paris Agreement, without any better alternatives and also lowering the world's already low opinion of US capacity to durably bind itself to international agreement.
Normally, the Secretary of State has the lead here, but not always.
People more qualified than me can chip on what Bush's FP views were before 9/11. But the Bush administration is clearly identified with the neocons, from Cheney to Rumsfeld to people like Feith (an excellent book to read about the hubris animating the neocons even though Feith is oblivious to their own naivety).
Paradoxically, the person most in charge of FP, the Secretary of State, Colin Powell, did not align enough with the neocons so got sidelined (post-invasion Iraq and Afghanistan governance was largely Pentagon-driven).
This group can have an outsized influence on US FP, illustrated by jumping into the Iraq invasion without ensuring a stable Afghanistan first, which was a decision arrived at by a small group. But that circle tends to change from administration to administration.
No, Congress has no direct role in US FP. Aside from ratifying treaties that is, which they rarely do. If JCPOA had been constructed as a more formal, congress ratified, agreement, perhaps Trump's mess could have been averted.
Congress is strongly motivated by fairly static electoral considerations and will not go out on a limb. This again brings a certain consistency, perhaps sub-optimal, but not nefarious as implied by this question. Relations with Cuba, Iran and Israel come to mind - they are all fairly frozen (hard to see Congress backing Bush Sr in his squabbling with Israel about Palestinians late in his administration, for example).
Congress can also be penny-wise and dollar-foolish. Like when Afghanistan aid plummeted after the USSR was booted out and the country was essentially left to poverty and warlords, thus setting the stage for Taliban 1.0 in 1994.
The US State Dept has two sorts of ambassadors: career and political appointees rewarded for supporting the POTUS. The political appointees can be out of their depth, but one of the most famous blunders, not warning Saddam to back off Kuwait was a professional diplomat's.
Below the ambassadors, career State staffers will try to implement US FP decisions. There is both considerable bureaucratic inertia - as can be expected. And also the need to actually deal with the situations as they exist, not as the other political actors wish they were.
This will, again, stabilize FP. Like any bureaucracy and real-world challenges, really.
Not a group per se, but certainly an influence.
In the past they've included such things as countering Communism, securing oil supplies, promoting trade beneficial to the US and, mostly, promoting democracy abroad (both for ideological and self-interest reasons).
That also promotes a certain "stickiness" in US FP, at least from its foreign counterparts: the unethical ways the US used to suppress Communism in Latin and Central America have poisoned relations with many of those countries.
Last, but not least, US FP is influenced by the views of the US electorate. Bush very well may have won his 2000 election due to a little Cuban boy named Elian Gonzalez. US reluctance to tackle climate change - except by throwing subsidies at it - stem directly from how unpopular it would be to do so.
Many of these factors apply, to lesser or greater degrees, to the US's democratic peers. The US is not that unusual, except in its self-identified exceptionalism and its relative importance on the international scene.
Last, while it's popular to criticize the US, the behavior of Western nations in places like Africa (arms selling by the UK and France to dirt-poor nations for example) leaves much to be desired.
And that's before we get into FP luminaries like China (support for Myanmar, North Korea, border clashes, Taiwan, the Nine Dash Line).
Or Russia. Whose leadership is apparently worth quoting on good governance here.
p.s. I've only read The Israel Lobby and U.S. Foreign Policy by Mearsheimer. While I mostly agree that the US does not benefit all that much from the alliance - note for example the near total absence of US bases there - it is rather obvious that following his guidance in that matter would be electoral suicide. The, justified, sympathy warranted to Israel, after Europeans essentially tried to wipe Jews out during the Holocaust and the lack of sympathetic Palestinian leaders certainly keeps US FP going in a certain direction, without much need for a "BLOB".
Nor does his tolerance and excuse making on behalf of Putin since his aggression on Ukraine indicate that his "optimization" would be necessarily all that ethical. Or productive.
p.p.s. Oliver Stone.
Like Chomsky, any person following international relations would know that Stone has made a long, and lucrative, career out of criticizing the US. Without much apparent qualifications to do so and with a strong tendency towards conspiracy theories:
“I wonder if the U.S. is setting a stage of a low-yield nuclear explosion, of unknown origin, somewhere in the Donbass region, killing thousands of Ukrainians. Of course… to blame Russia… regardless who launched the device.”
Citing him is doing this question no favor and bolsters the case for calling it out for aim to discredit.