Conversation so far:
What has Romney been doing?
Willard Mitt Romney is an American politician and businessman serving as the junior United States senator from Utah since January 2019
Where has Mitt Romney been active?
He previously served as the 70th Governor of Massachusetts from 2003 to 2007 and was the Republican Party's nominee for President of the United States in the 2012 election.
What are Mitt Romney's political intentions?

Question: When did he run for president?
Self-contained rewrite: When did Mitt Romney run for president?