The government of the United States has three branches: the Legislative Branch (which consists of the Senate and House of Representatives), the Judicial Branch (which consists of the Supreme Court and other federal courts), and the Executive Branch. The purpose of the Executive Branch is to carry out laws. It consists of the president, the vice president, the cabinet, and other federal agencies.
In some aspects of government, the Executive Branch is stronger than the other two branches. For instance, the president is the leader of the federal government, the head of state, and the Commander in Chief of the Armed Forces. He has the power to appoint judges and nominate heads of federal agencies. He also has the authority to veto laws that Congress passes.
However, the founding fathers wrote into the US Constitution a series of checks and balances so that ultimately no branch of the government could be stronger than any other branch. All of the strengths of the Executive Branch listed above are checked by powers that the other branches have. For example, although the president is the commander-in-chief of the armed forces, the duties of Congress include voting to declare war and appropriating funds for the military. Executive actions cannot take place unless the money for them is approved by Congress. Additionally, peace treaties are not valid unless they are ratified by the Senate.
Although the president nominates federal judges and other officials, Congress has to confirm the nominations. The president can veto legislation, but Congress can override presidential vetoes by a two-thirds majority vote in both houses. Congress also has the power to impeach the president or other members of the Executive Branch for crimes committed while in office.
We can see, then, that the Executive Branch is stronger than the other branches under certain circumstances or while carrying out certain duties, but in the overall workings of government, no branch is stronger than any other due to the checks and balances put in place by the US Constitution.
In theory, all three branches of the U.S. government are equally powerful. Whether this is true in practice is more difficult to say. However, the executive branch has the illusion of being the most powerful branch because its powers are the most apparent and are discussed more often because they are easier to see and comprehend.
For example, the executive branch is correctly considered the “face of the nation” because it wields a lot of power in international affairs. This makes the President of the United States—the head of the executive branch—seem very powerful. For example, it is the President who gets to meet with foreign dignitaries and go on official trips.
However, in quieter but arguably more important matters, the executive branch often takes a backseat to the legislative branch. After all, the executive branch's official role is to execute the laws, not to make them—that is the role of the legislature. To that extent, Congress gets to dictate the legislative landscape more than the executive branch.
It is by no means a fact that the executive branch is the strongest branch of the American government. You could argue that it is, but you could also argue that it is not. After all, the president has fairly limited powers. The most important example of this is the fact that he (or someday she) cannot make laws. However, we can argue that the executive branch is the strongest branch.
One reason for this is that the executive branch carries out all the laws. If the executive branch decides that it does not want to enforce a law very strictly, it can probably get away with that unless Congress really decides to work hard to force it to do so. This is how, for example, President Obama can say that the US government will not prosecute marijuana growers in states where marijuana is legal.
Another reason for this is that the executive branch can veto bills. Today, we know that the Republicans in Congress would probably be able to get enough votes to repeal Obamacare. However, with President Obama in the White House and able to veto laws, there is no way such a law could ever be passed.
A third fact is that the executive has almost complete power over foreign policy. The president can negotiate treaties, though the Senate does have to ratify them. The president can command the military without Congressional approval. The president has almost unlimited ability to do what he or she wants in this area.
The most important reason why the executive branch is strong is because the president is the most visible leader for the nation. Only the president is voted for by people from every state. Most people know who the president is, but only relatively few people can name many members of Congress. When the president gives a speech, it is big news but when a member of Congress gives a speech it is not. Therefore, the president has much more ability to lead the nation and to try to persuade people to support certain laws.
In these ways, it is at least possible to argue that the executive is the strongest branch of government.