Complex sentence: Years after the Clintons left the White House, the mystery thesis held its allure; for example, in 2005 Clinton critic Peggy Noonan wrote that it was the Rosetta Stone of Hillary studies.
Split into simpler sentences: Years after the Clintons left the White House, the mystery thesis held its allure. For example, in 2005 Clinton critic Peggy Noonan wrote that it was the Rosetta Stone of Hillary studies.