The people of the United States have powers given to them by the Constitution that allow them to have their own set of checks and balances on the branches of the Federal government.
The people of the United States can bar an amendment of the Constitution by Congress if 3/4 of the states refuse to ratify the amendment.
The people also have the ability to vote on their Representatives every 2 years and their Senators every 6 years. By choosing their Representatives and Senators, the people indirectly influence who is part of the Judicial branch.
To ensure that one branch of the Federal does not become dominate over the others the Federal system of government was created with an internal set of checks and balances consisting of powers reserved specifically for each branch of the government.
Executive Branch Powers:
The Executive branch can veto acts of Congress by the President choosing not to sign the act into law. This allows the Executive branch some control over what laws Congress creates. The Executive branch has the ability to appoint Federal judges and issue pardons, which gives it influence over the actions of the Judicial branch.
Legislative Branch Powers:
The Legislative branch has the power to impeach and remove the President from office if the President has committed crimes of treason, high crimes, or misdemeanors. (Interestingly, the definitions of ‘high crimes and misdemeanors’ is not given in the Constitution which leaves open to debate as to what kinds of crimes fall under those categories.) Congress can also override Presidential vetoes by voting on a law again and passing it with a 2/3 majority. Congress must approve the appointment of Federal judges, which allows them to influence who hold office in the Judicial branch.
Judicial Branch Powers:
The Judicial branch can declare acts of the President unconstitutional, which removes them from the law. The Judicial branch can also declare laws passed by Congress to be unconstitutional in whole or in part. These powers allow the Judicial branch to have influence on the actions of both the Executive and Legislative branches.