WASHINGTON - The special counsel investigation of links between Russia and President Trump's 2016 election campaign should continue without interference in 2018, despite calls from some Trump administration allies and Republican lawmakers to shut it down, a prominent Republican senator said on Sunday.Lindsey Graham, who serves on the Senate armed forces and judiciary committees, said Department of Justice Special Counsel Robert Mueller needs to carry on with his Russia investigation without political interference."This investigation will go forward. It will be an investigation conducted without political influence," Graham said on CBS's Face the Nation news program."And we all need to let Mr. Mueller do his job. I think he's the right guy at the right time."