So now that we know what the three branches of government do, let's delve into how they check each other. Supposedly, we have a strong system of checks and balances to prevent any body of government from getting too powerful. As time goes on and our President (*bites tongue* still hard to type...) takes advantage of his power, it seems like those systems may be eroding. But before we investigate that, let's look at how the Founding Fathers intended those checks and balances to work.
Let's start with this handy dandy graphic:
Here, the Legislative Branch has been placed at the top because when it comes down to it: the Legislative Branch has the most power. Sure, the President seems to have the most power...after all, they're the leader of the Free World! But when you consider the individual powers of each branch and the power they have over each other, the Legislative Branch comes out on top.
I mean they literally have the power to impeach the President! They can impeach Supreme Court Judges! They can reject the candidates the POTUS nominates for Supreme Court or their Cabinet! They can refuse to allocate funds for initiatives the President wants to enact! And if the President vetoes a bill Congress wants to put through, they can come right back with a 2/3 majority vote and make it happen anyway! The Legislative Branch can obstruct the other two branches in so many ways, it can be really hard to pass anything if the it is mostly made up of the opposing party. We've seen this take place in many administrations, most recently, when President Obama was constantly battling with a Republican Majority Congress.
If we continue down the line, the Executive Branch has the most power after the Legislative. If you think of the President as a Casting Director, it's their job to cast the Cabinet and any open Supreme Court seats. My dream Cabinet appointees would be Rihanna as Secretary of the Treasury, Joanna Gaines as Secretary of the Interior and Neil Degrasse Tyson as Secretary of Education:
The Executive Branch is composed of several federal agencies like the EPA, CIA and Department of Justice, which the President oversees on a day-to-day basis. The POTUS can issue Executive Orders and carry those out through those agencies as long as the Supreme Court does not rule them unconstitutional, which happened with the Muslim Travel Ban. The other big power that the Executive Branch has is to conduct foreign policy. Most foreign relations and diplomacy issues go through the Executive Branch. If the President wants to declare war, they have to get permission from Congress--which happened when George W. Bush declared war on Iraq in 2002.
The last branch with the smallest amount of power is the Judicial Branch. It has limited power because there aren't a lot of things the Judicial Branch can do other than interpret the law and declare bills or executive actions unconstitutional. So it's not a broad range of powers but the power they do wield can stop a President or Congress in its tracks. Several monumental changes in history have come about through the Supreme Court; for instance, when they deemed the ban on same-sex marriage unconstitutional in all 50 states in June 2015. Because of this decision, same-sex marriage was finally made legal and commemorated by the White House with this beautiful rainbow display:
So as you can see, each branch has been carefully designed to be able to check the other from becoming too powerful. The only instance where these checks and balances might not have much of an effect is in our current scenario: A Republican majority in the Senate and House, a Republican President, and a Supreme Court with a more conservative background. It can also be vice versa, but currently we have a majority Republican administration.
Obviously, this doesn't have to put a stop to checks and balances just because there's a Republican majority. If the Legislative Branch is unhappy with the President's performance, they could make efforts to impeach him. Right now, there are many instances that have people calling on Congress to impeach POTUS, but it hasn't happened yet. In fact, Congress hasn't made much effort to contest POTUS on his most controversial actions like the Travel Ban and the Repeal of the AHCA. This is probably because the Republican party is afraid of losing power so they would rather keep an incompetent, xenophobic, narcissist in charge than make themselves vulnerable to losing their seats. This is, unfortunately, a classic example of Party over Country. The main check we've seen so far has been through the Judicial Branch, most notably in the Ninth Circuit District Court blocking the Travel Ban. So even though our government retains its structure of checks and balances, the Executive and Legislative Branches are working together to enact the Republican agenda they weren't able to push under President Obama. That is why, we are not seeing the push-back that some expected (or hoped) would occur should an inexperienced leader like Donald Trump become President.