In the United States government there are 3 branches of government, the power given to the central government is divided among these 3 branches. Each of these branches are given powers so that they can check the powers of the other 2 branches ensuring that one branch doesn't become to powerful One of these branches is the legislative branch this is the branch that includes congress, they are responsible for making laws. The second branch of government is the executive branch this is the branch that includes the president, they are responsible for carrying out laws. The last branch of government is the judicial branch, this branch includes the Supreme Court they are responsible for making sure laws are constitutional. There many different ways at which each of these branches check the powers of the next branch, they include appointing new members to each branch, vetoing laws proposed by a branch, declaring a law unconstitutional and many other different powers. The legislative branch just like every other branch in the government has the power to check other ones and is checked by the opposing branches.
This legislative branch checks the powers of the executive branch in many different ways ensuring that they do not become overpowering. One way in which the legislative branch checks the power of the executive branch is if congress "the legislative branch" decides that the president is not doing his job to the full extent that he should, they have the power to impeach him from office so that his job will be done right by the person next in line for the job. One other power that the legislative branch has is the power to override a veto with a 2/3 vote. This means that if the president decides to veto a law proposed by congress they have the power to override that veto w/ a 2/3 vote. One way in which the legislative branch checks the powers of the judicial branch is if congress decides that a certain judge isn't doing his job properly they have the power to remove them from their job. One other power that the legislative branch has over the judicial branch is they have the power to approve or reject the appointments of new judges, this means that if they do not want a certain judge to be appointed to the supreme court they have the power to deny him of his job.
The executive branch also has many powers over the other 2 branches. One power that the executive branch has over the legislative branch is, if congress decides to create a new law the president has the power to approve or veto this law if he doesn't like it. The executive branch also has many powers over the judicial branch. One of these powers is the President has the power to appoint new judges if he feels that there is the need for a new member to the Supreme Court. One other power that the president's branch has over the Supreme Court is the power to pardon someone. This means that the president has the power to excuse someone from their crime that they committed if the Supreme Court decided that that individual was guilty.
The Supreme Court as well as the other 2 branches has many powers over their opposing branches. One power that the Supreme Court has over the executive branch is the power to declare any actions done by the executive branch unconstitutional. The Supreme Court also has many powers over the legislative branch. They have the power to declare any laws introduced by congress as unconstitutional.
In all the system of separating the powers of government is good idea not one branch is able to become to powerful but each branch still has many powers.