Investigators at the website researched the ad's allegation that Blunt secretly slipped wording into the Homeland Security Bill which would benefit his lobbyist girlfriend's client, Phillip Morris:
Allegations of "secretly inserting" provisions into bills are often a matter of interpretation. In this case, hours before a final vote on the Homeland Security Bill, Blunt proposed a provision that had not been vetted in a committee meeting or in legislative markup sessions. It may have been added in a way that meant there was little notice and little discussion, but that doesn't necessarily add up to "secretly."
Blunt may argue the provision was a legitimate homeland security concern and that a similar version later received bipartisan support. But the Blunt provision was opposed by some anti-tobacco groups, who viewed it as special interest legislation to benefit big tobacco. And we note that those groups did not oppose the later legislation.
When you date (and later marry) a Philip Morris lobbyist, when you have a son who works as a tobacco lobbyist, when you accept hefty sums of campaign money from tobacco executives, and then you add an 11th hour provision that some view as pro-big tobacco, you leave yourself open to the kind of criticism raised in the ad. "Secretly" may be overstating how Blunt acted, but the ad's other points are backed up, so we rate it Mostly True.