Pashuteh Yid,
This is a subject of great debate, but my own take on the subject is that they were are formula for survival thru most of the long Galus. We would be good citizens and the nations would not oppress us excessively. There was no formal oath as there was only the formal acceptance of the Torah at Sinai. In eastern Europe since the 1800’s the oppression became excessive. All 4 of my grandparents fled Europe which had become a burning house as far as Jews were concerned and came to US & Canada.
There are those who argue that the Shalosh Shevuos are binding upon us even when the nations violate them. If so, they become effectively a suicide pact for us, not a tool of survival.
We are now at year 5770 – 2010 CE and the Jewish State is a Fait Accompli.
The American Jewish community is also an important part of our survival and we are obligated to be good citizens.