any guesses why constitution gives ...?

Question

any guesses why the constitution gives federal courts the power to hear cases where a party from one state sues a party from a different state?

The judges of each state take oaths to support the Constitution, meaning that the STATES constitutions and laws should NOT CONFLICT with the laws of the FEDERAL constitution, therefore in case of a conflict, state judges are legally bound to honor the federal laws and constitution over those of any state.

Answer 1

This is called "Diversity jurisdiction" and is in Article III, Section 2 of the Constitution. It first exercised that power in the Judiciary Act of 1789. It was simply to give citizens of different states an equal playing field in a court. Now, it is only exercised if the amount in controversy is more than $75,000. It's codified in 28 USC Section 1332. The amount in controversy has been increased over the years as a simple practicality. Also, until the Judiciary Act, Federal Courts did not have trial jurisdiction--only appellate jurisdiction.
There's some disagreement in the answers in what law is applied. If it's true diversity jurisdiction, there is no federal issue and the law of the state where the act occurred is applied. Normally, these are simple contract and damage cases and there little differences between the state laws. In Erie Railroad v. Thompkins, the U.S. Supreme Court rejected an attempt by the federal district courts to create a federal common law for diversity cases. Therefore, diversity jurisdiction only gains the litigants a neutral forum, not an advantage in the law applied to the issue.

Answer 2

Because the laws are generally different in each state. Allowing the case to be heard in one state over another would be an unfair advantage. Therefore the Federal Court is used as sort of a neutral ground.

Answer 3

In order to ensure that state judges are not biased in favor of parties from their own state over "foreigners".

The fact that the laws are different in different states doesn't matter, because the federal judge is obligated to apply state law.

Answer 4

The Constitution provides the laws for the courts to have jurisdiction over cases within the territorial and extra-territorial boundaries of the state. The law maybe hard but it is the law.