In the Supreme Court decision Marbury v. Madison of 1803, the court took the power of judicial review and the power to declare acts of congress unconstitutional.

Separation and checks and balances were created to ensure that one single branch of government, the executive, legislative, and judicial from gaining too much power over another. It prevents one person, or one group to influence government too much.

The House of Representatives was the only branch of the national government that had direct election of the people. All others were either appointment or indirect election. For instance, Senators were initially elected by state legislatures and the presidency remains indirect through the Electoral College.

Article II of the U.S. Constitution deals with the powers of the presidency, though Article I does deal with some of the president’s powers in regards to passing legislation.

The states are typically responsible for several key categories of public policy – including morality and societal issues (such as divorce) and familial matters (including child care and child labor bans). Currently, state governments have also assumed more control over welfare distribution, matters of healthcare, educational standards, and measures to preserve the environment. Throughout the course of American history, the states have traditionally served as experimental and/or visionary developers of many policies, whose success led to their adoption by, first, other states, and then eventually, the national government itself. For example, an individual state first devised the idea of the minimum wage, while another pioneered environmental protection legislation; the national government therefore often looks to the states for salient public policy inspiration.

The president, the head of the executive branch, has power to veto any bills passed by the legislature. Neither the states nor the judicial branch are granted the power of the veto under the Constitution. The Senate is a part of the legislature and therefore does not have the power of the veto.

The president, the leader of the executive branch has the power to make foreign treaties. The states and the judicial branch have not power over foreign affairs. Although the Senate must approve treaties, the legislative branch cannot negotiate and create treaties. 

Under the Constitution, only the House of Representatives can start new tax bills, not the Senate. The President is unable to "raise revenue" via taxes under the Constitution. The States can levy their own taxes that affect the citizen of that state, but cannot levy federal taxes.

According to Article 1 Section 3 of the Constitution, the Senate has the power to try all impeachments. The Supreme Court can only rule if a law is Constitutional or not, and has no power over impeachments. The US Department of Justice also has no power over impeachments. Although the House has the power to impeach government official, the Senate is the only chamber of legislature that can conduct the impeachment trials.

The judges listed in this answer all serve in the Federal Court System and are subject to the roles set forth in Article III of the Constitution. The other answers are incorrect because the President can appoint a Supreme Court justice at any time during his term of office in accordance with Article II of the Constitution. A justice who is nominated by the President must be approved by the Senate and his or her position is not temporary. A special master is appointed by a trial judge to review materials in dispute during a trial. The special master is a neutral judge with no connection to the trial. The Chief Justice of the Supreme Court presides over impeachment proceedings as part of his duties in Article III of the Constitution.