Even though polls show that the American public is at the moment against impeaching President Donald Trump, historical polling data obtained by the Washington Post's Greg Sargent shows that could change very quickly.
In breaking down data on the impeachment of former President Richard Nixon provided by Gallup, Sargent finds that most Republican voters were consistently against impeachment right up through Nixon's resignation in 1974.
However, the polls also show big swings among independent voters, who went from being overwhelmingly against impeachment in the middle of 1973 to having a majority in favor of impeachment just over one year later.
"In some ways, this offers more grist for believing public opinion can be shifted again," Sargent writes. "Note that the shift was more substantial among independents, eventually amounting to a solid majority, than it was among Republicans... The Gallup numbers on Nixon suggest big shifts among independents are possible and show that a substantially larger percentage of independents now support impeachment hearings than at the outset in Nixon’s day."
Sargent then asks Princeton historian Julian Zelizer to explain exactly how public opinion on impeachment shifted -- and he said that holding impeachment hearings was a key factor.
"It’s clear from the data that impeachment proceedings provided the jolt that shook the public, among independents in particular,” Zelizer explains. "An independent by nature is not going to make a quick decision. Impeachment proceedings and then the approval of articles of impeachment are what ended up moving independents... This wasn’t Congress waiting on the public... It was the other way around -- Congress provided guidance to the public."