Donald Trump committed the "most grievous constitutional crime" of any US president when he incited supporters to storm the Capitol last month, Democratic prosecutors said Monday on the eve of his Senate impeachment trial.

"The evidence of President Trump's conduct is overwhelming," the nine House impeachment managers prosecuting the Republican leader said in their final pre-trial filing.

"His incitement of insurrection against the United States government -- which disrupted the peaceful transfer of power -- is the most grievous constitutional crime ever committed by a president."

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