Why is the commerce clause written in 1787 still adequate to meet the needs of the nation in the 21st century?

The Commerce Clause gives Congress the power to regulate trade with other nations. This is very relevant in the 21st century because we are in a era of globalization in which trade among nations is paramount for development. This is why nations sign trade deals, and the US is no exception to this. In fact, at the moment, the US is negotiating several trade deals, for example with China, a country that already has great economic power.

according to classical republican political theory, which democratic republics would function best?

a.   small republics, with people who had similar interests

b.   large republics, with people who had competing interests

c.   republics made up entirely of landowners

d.   republics made up entirely of servants

where's the