WASHINGTON >> President Donald Trump’s former campaign chairman, Paul Manafort, took the unusual step today of suing the special counsel and asking a federal court to narrow his authority.

The move comes as Trump tries to cast the investigation as a politically motivated witch hunt that has cast a dark cloud over his administration and, in his view, the country. The president said last week that he hoped the special counsel, Robert Mueller, will treat him fairly.

Mueller is investigating the Russian government’s meddling in the 2016 presidential election and whether anyone close to Trump was involved. As part of that investigation, prosecutors indicted Manafort on money laundering charges related to years of foreign lobbying — but not related to Russian election interference or the Trump campaign.

Manafort argued in the lawsuit Wednesday that Mueller had gone too far. He sued both Mueller and Rod Rosenstein, the deputy attorney general who appointed him. The lawsuit said Rosenstein had improperly given Mueller the authority to investigate “anything he stumbles across while investigating, no matter how remote.”

A spokesman for Mueller had no comment on the lawsuit.

The charges against Manafort date back years, well before he began working for Trump. His lawyers argue those charges exceed Mueller’s jurisdiction because he was authorized only to investigate separate matters if they arose from the Russia investigation.

That theory echoes comments made by Trump, who has said that Mueller cannot investigate his family’s personal finances.

Manafort asked a federal judge to reject Mueller’s appointment as overly broad. He asked a judge to dismiss the indictment against him and issue an order prohibiting Mueller from investigating anything beyond Russian meddling in the election.

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