First, no, they're not puppets. Having said that, they are in a system with very powerful expectations and pressures available.
First, finance. The markets exert enormous power and influence over the President. There's a reason Wall Street staffs the Treasury Department, why our Democratic President's Secretary Treasury is a former chairman of Goldman Sachs and the Republican President before him's Treasury Secretary was the Chairman of Goldman Sachs, why they call it 'Government Sachs', for a few anecdotes.
The thing that hurts or helps a President most politically is how the economy does, and Wall Street can greatly affect that easily.
An example of how they can do even more was how in Venezuela when the coup failed and they wanted Chavez out because of his programs for the poor, the wealthy interests organized an economic shutdown that lasted for months to pressure the people to remove him. It didn't work, but I'd bet it might here.
We've seen the ongoing reversal of policies put in place to check Wall Street after the Great Depression, starting largely with Reagan - which quickly led to the S&L crisis.
Since then it's just been more of the same, deregulate and have more grabbing of money, with a couple exceptions of new rules in response to big messes like Enron or the financial crash, greatly weakaned by lobbying. It was said there were 25 lobbyists pushing to weaken the latest regulation bill for every one for the bill.
Second group - the military industrial complex is hugely powerful. When FDR built the Pentagon, he wanted it to be only a temporary office, saying that allowing the massive industry an office that close to Congress would create too much pressure on Congress; not long after, Eisenhower thought that had happened enough he made his farewell address as President at the height of the Cold War about the excesses of that industry corrupting our government.
Not that this very powerful two term President who had led the allies in WWII was powerful enough to do much about it but a speech.
JFK did make some reforms when it was an even more coistered culture. When his Secretary of Defense McNamara told the Pentagon to show him the nuclear war plans, which he suspected were dangerous at launching a massive nuclear war on a hair trigger if there was any conflict in the tense Berlin situation, the Pentagon told him no, it's our plan, not yours. Had had to have JFK order the Pentagon to show him the plans - which were that bad.
JFK ordered the creation of the Defense Intelligence Agency to get a little more control over the branches - a good book on it is "House of War" written by the son of the general JFK had create the agency. JFK also created a position of liaison between him and the Joint Chiefs of Staff, filled by a trusted General Maxwell Taylor. Nonetheless Kennedy was constantly under pressure from the industry, and he did approve large military budgets.
When LBJ became President, he was not the same at saying no - he told the JCS, 'you can have your war in Vietnam after re-election' while privately saying we couldn't win.
The military industry has operations in every state in the country, in most if not every district and has huge influence over Congress as well.
The way it works more is that the President needs allies - he has to 'build support' to change things. When liberals told FDR he wasn't doing enough for the people and giving in to powerful interests, he told them to build the political demand for him to do more if they wanted it. Presidents since including Obama said the same thing.
In the period of corruption a century ago, when Teddy Roosevelt wanted 'reform for the people', he didn't get it done as President; he spoke out after he was President, was uanble to get the Republican nomination again, and had to run as a third party candidate. He lost. That's more the story of 'presidents who want change'.
This is one of the corrupting influences of high concentration of wealth - the people are drowned out by the few with all the money.
As popular as JFK was, he had a very hard time getting much passed in Congress, despite nominally controlling both houses.
Presidents tend to have powerful interests who helped them gain power; different presidents and parties, different presidents. But as an example, US corporations who didn't like the new President in Chile, Salvadore Allende, talked to each other and selected Coca Cola - who Nixon worked for as a lawyer between losing the race for governor and becoming President - and told him they wanted Allende out. Nixon ordered his staff to make it happen. It did, after bribery failed, violently.
But these are the sorts of influences on a President - not mysterious secret societies, groups of Rothschilds and such.
These organizations wield some power with things like hiring advertising firms that manipulate public opinions.
When Clinton wanted healthcare for the people and the insurance industry didn't, they hired advertising and brought us 'Harry and Louise' and Clinton's ratings plummeted.
When Obama wanted a plan, he did it differently, trying to buy off the special interests, and Harry and Louise appeared again, according to the deal, to support the plan.
When the first President Bush and the Kuwaiting government kicked out by Saddam wanted to reverse strong public opposition to war in Iraq, the Kuwaiti government hired an advertising agency, the branch headed by Bush's former chief of staff, and they launched a campaign that lied to Congress and the American people, having the daughter of the Kuwaiting Ambassador pretend to be a hospital worker testify in tears about watching Iraqi troops take babies out of incubators. Public opinion shifted.
No one was prosecuted for lying the US into war.
If Kennedy was assassinated, it wasn't for any Fed policy, it was for his being viewed as a security threat by an out of control security state. That's changed - it's not as if Presidents are threatened to be killed. Those were wild times, when such a thing was possible.
I did make up a fun conspiracy theory, though, that Bush was 'put in his place to follow orders' by the time he choked on a pretzel and was found unconcious being an incident proving to him he could be killed if they wanted. It's meant humorously, though, not an actual conspiracy.
What tends to happen to President who want a lot of change against powerful interest is a war for public opinion. See Clinton on healthcare for how that can go.
So Presidents don't easily do those things. When LBJ did on civil rights, he said he had just handed the 'solid south' of Democrats over to Republicans - and the White House to Republicans for decades to come (he was right. The first non-southerner Democrat to win the White House after 1964 was Obama, and 5 of 7 presidents were Republicans, one of the Democrats probably only winning because of Watergate and the pardon).
When JFK wanted to do something on civil rights, which was a big change, he faced public opposition; opinion polls said he was 'pushing too fast'. Even when he tried to enforce the court orders, southern governors campaigned on standing in defiance, forcing Kennedy to send federal forces and nationalize the state forces. He faced the defeat of almost anything in Congress if he pushed a civil rights bill. He slowly built support for it, including his national address on the issue calling for support.
Despite all that, he never got it passed; that took LBJ. There was an increase in support after JFK was assassinated.
Kennedy did plan to overhaul the intelligence agencies - with the out of control CIA first on the list - in his second term. He planned to likely reverse US policy on Vietnam - in his second term. (Just as LBJ waited for re-election to start the major war). But such an overhaul would be very difficult today - Bush made a major overhaul but it was only to greatly expand the agencies and their budgets.
Fact is, these entrenched interests - wealth, corporate interests, security state - come to view change by the President as a threat. They say that what lobbyists mostly do is prevent any changes - not get changes. Presidential candidates need the money of these interests to have almost any chance in the election - anti-Wall Street crash 'for the people' Obama had Goldman Sachs as his top private contributor.
So maybe we could use some outside the system wealth liberal to come in and change corruption? Ask yourself how demonized is someone like George Soros.
That's how these things get corrupted - when a pro-democracy group, ACORN, wanted to do what's more American than about anything else - increase voter turnout among the underrepresented poor - monied interests opposed it, and they were savaged and put out of business - while one of the most un-American activities - suppressing voting in the interest of the wealth groups - is now going on at historic levels in a nationally coordinated campaign by the private corporate political 'ALEC' organization.
Most of the media doesn't say a word against that.
That's the strength of these organizations; they don't kill good presidents, they filter who can get elected and keep them in line by manipulating public opinion, Congress, etc.
Craig234