To be a member of the House of Representatives you have to have been a citizen of the us for many years

The Constitution requires that Members of the House be at least 25 years old, have been a U.S. citizen for at least seven years, and live in the state they represent (though not necessarily the same district).

Explanation:

the historians cited in the article all agree with one another about the cause of the civil war. despite coming from different backgrounds and cultures, the historians agree that slavery was the root cause of the civil war. the fact that all these historiansgenerally agree with one another makes their shared viewpoints more reliable and valid, especially because the historians have different backgrounds and all work for the well-respected institutions of howard university, clemson university, and the university of colorado.