If anybody has been wondering why Barr has been tardy taking control of the SC legacy prosecutions, Warren's nonsense comment should clarify it.
She is reprising the President Trump's impeachment, in which PDJT was accused of not following Vindman et al.'s foreign policy directives.
Barr cannot stage an "intervention" over the Stone case, because anything he constitutionally does cannot be construed to be intervening.
Warren and those who put her up to this are trying to make Barr doing his job an implicitly impeachment-worthy event, with the obvious goal of overthrowing PDJT's presidency.
In other words, this is simply a "do-over," another brick in the on-going coup!