Ryan was commenting on what The Washington Post's Ed O'Keefe reports is the most organized effort yet to stop Trump from becoming the Republican presidential nominee.
Dozens of Republican delegates who will be voting for the nominee at their July convention want to change convention rules to allow delegates to vote for whomever they want — instead of the candidate who won their state's nominating contest.
Ryan is the chair of that convention, which means he will essentially referee it. According to his interview with Todd, that means he will "just play it by the rules," apparently whatever those rules may say. Ryan has endorsed Trump and told reporters this past week that he has no plans to rescind his support.
Trump himself tried to throw cold water on that plan. In an interview with NBC's Hallie Jackson that also aired Sunday on "Meet the Press," Trump said he doesn't believe delegates are planning to out maneuver him for the nomination and questioned whether it was even "legal."
"I competed with a lot of the establishment people, I beat all of them, and now a couple of them would like to come through the back door?" he said. "It's awfully hard when I won .. 38 .. states, and somebody else won none, and they're going to be the nominee? I don't think so."
Ryan also told Todd that House Republican lawmakers should follow their "conscience" when deciding whether to support Trump.
O'Keefe reports that by using the word "conscience," Ryan could give leverage to delegates' plans to block Trump, because that's how they might be freed up to vote for anyone: by passing a "conscience clause."
The anti-Trump push comes as Trump has careened from one controversy to the next since mathematically clinching the nomination in May. His poll numbers have taken a sharp turn downward against presumed Democratic nominee Hillary Clinton, and a Washington Post-ABC News poll this past week found his unfavorability ratings at a campaign high.