Was Athens or Sparta more influential in the making of the US?

Since there is a lot of talk these days about the role of the US Senate in the US political systemics, consider this:

Which political system, the Athenian or the Spartan, was more influential to the US Constitution and the making of the US in general?


And since we are on the topic:

a) Who was the "father" of Democracy: a) Cleisthenes b) Pericles or c) Leonidas?

b) Why did Sparta beat Athens in the Peloponnesian War (431-404 B.C)? Why did Sparta lose to Thebes at Leuctra (371 B.C.)?


Feel free to tweet me your replies @npanayotopoulos (via Twitter of course).