Neither the original column by Andrew C. McCarthy in National Review nor a follow-up directly claimed that Mr. Obama or any of his political appointees had anything to do with the “spy” even if the F.B.I. did have an informant. But that theory fits the larger case that a politically compromised intelligence apparatus manufactured an investigation.
The president has advanced the premise in sometimes sensational and uncorroborated ways, as when he accused Mr. Obama of wiretapping Trump Tower, an assertion dismissed by Mr. Trump’s own Justice Department. But questions persist about the F.B.I.’s use of a dossier financed by Mrs. Clinton’s campaign and the Democrats to obtain a secret warrant against an adviser to Mr. Trump.
To Mr. Trump’s allies, that was, yes, bigger than Watergate. “Our sources are telling us that the abuse of power is far bigger than Watergate,” Sean Hannity, the Fox News host and friend of Mr. Trump’s, said in January. “I have long said it is worse than Watergate,” agreed Representative Steve King, Republican of Iowa.
Mr. Trump’s theory of the case has been bolstered by some investigators who have gotten in trouble. Two former members of the team working for the special counsel, Robert S. Mueller III, wrote text messages that expressed political views critical of Mr. Trump. Andrew G. McCabe, the former deputy F.B.I. director, was fired for not being forthcoming with an inspector general looking into his conduct.
The bigger-than-Watergate analogy, of course, is one of the most overused tropes in American politics. To hear some tell it, Chappaquiddick, Iran-contra, the Keating Five, Whitewater, the Bill Clinton-Monica Lewinsky scandal and the C.I.A. leak case were all worse than Watergate. George W. Bush’s whole presidency was “Worse Than Watergate,” according to the title of a 2004 book written by none other than John Dean, the Watergate figure. Politico actually tabulated 46 scandals or other furors that have been declared worse than Watergate.
Among the most prolific purveyors of bigger-than-Watergate comparisons has been Mr. Trump.
Sheriff Joe Arpaio’s investigation into Mr. Obama’s birth certificate “could dwarf Watergate,” Mr. Trump wrote in 2012.
“Benghazi is bigger than Watergate,” he wrote a few months later.
Mrs. Clinton’s private email server “is bigger than Watergate,” he wrote in 2016.