Republicans could file challenges if Biden replaced, Speaker Johnson says

House Speaker Mike Johnson reiterated Sunday that any attempt by Democrats to sub in a new candidate in place of President Joe Biden is likely to be met by legal challenges.

Speaking on ABC's "This Week," Johnson said, "Every state has its own system, and in some of these, it's not possible to simply just switch out a candidate."

Johnson's assertion, which echoed remarks he made during the Republican National Convention, suggests a strategy Republicans could be looking toward should Biden decides to withdraw from the presidential election. "I think in states where it can be contested, I expect that it will be, and they'll have an interesting battle on their hands,” the Louisiana Republican said Thursday of a possible switch.

Technically, Biden has not yet been formally nominated to be the Democratic presidential candidate and won't be until a vote of the delegates selected to the Democratic National Convention. Still, Johnson said there might be grounds for a challenge, given that Biden was the overwhelming winner of the party's primaries.

"I think they would run into some legal impediments in at least a few of these jurisdictions," he told host Martha Raddatz. "We'll see how it plays out."

Vice President Kamala Harris is a possible replacement on the ticket for Biden should he withdraw from the race. Johnson on Sunday declined to assail Trump for referring to her as "laughing Kamla" and "crazy" in a speech Saturday, the kind of personal attacks Johnson has said do not belong in the election process.

"I articulate things in a certain way and Donald Trump does as well," Johnson said, "but his grievances, as you said, are because he has been the subject of so many attacks."

When pressed on the matter, Johnson said Democrats are doing the same thing.

"We could run the tape of terrible things that Kamala Harris has said about Donald Trump, of course, and Biden as well, and everybody in the Democrat leadership," Johnson said.