Former Senator Alan Simpson (R) appeared on MSNBC's The Last Word Wednesday, where he called for an investigation into anti-tax crusader Grover Norquist's influence on the Republican Party.

Grover's anti-tax pledge has been signed by 235 House Republicans and 41 Senate Republicans.

"If Grover Norquist is more powerful than the President of the United States and Congress... he should run for president," Simpson said. "It's time now to peel all the layers of onion off of Grover Norquist."

"Who is he a slave to?" he added. "Somewhere that needs to come out very soon."

Watch video, courtesy of MSNBC, below:

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