The Declaration of Independence
There are many possible answers for this one! Only the national government can e.g. manage foreign relations, declare war or oversee trade between states and with other countries.
Have you ever heard about Louis and Clark and Sacagawea? Anywho after the territory was bought from France Jefferson, the president at the time, sent a group of men to explore the territory. They were led by Louis and Clark, they met an Indian tribe and an Indian woman helped them on their journey.
Answer:
Because of their oppression of exercising their voice under the rule of the British government, the American colonists believed heavily on the freedom of speech. They believed that the government should allow its citizens to vocalize their points of views through its representatives. As the American Revolution progressed the call for vocal freedom increased.
The Senate "cools" legislation from the house like a saucer cools coffee. The Senate approves all presidential appointments and ratifies treaties while the house initiates revenue bills.
The Senate has vital powers as stipulated in the constitution under the " advice and consent" provisions, Article II, section 2, to; ratify treaties which require a two-thirds majority of the senators present and a simple majority to approve important public appointments i.e., ambassador and cabinet members.