A federal judge tore into all of the legal arguments that a lawyer for President Donald Trump's former campaign chairman, Paul Manafort, made on Wednesday in his long-shot civil case to convince her that special counsel Robert Mueller's investigation has run amok and should be reined in.

"I don't really understand what is left of your case," U.S. District Court Judge Amy Berman Jackson said to Kevin Downing, Manafort's attorney, after peppering him with a lengthy series of questions.

Manafort filed a civil lawsuit on Jan. 3 in the U.S. District Court for the District of Columbia against Mueller and Deputy Attorney General Rod Rosenstein, the Justice Department official who appointed the special counsel, in a key legal test of how far Mueller's mandate extends.