In the specifics of allegations of insurrection against Trump it would annul Section 3 of the Fourteenth Amendment and in respect of all Presidents past and present it would annul Section 1 ‘deny equal protection under the law’ because a President, past or present, who is above the law could shoot somebody in the head on 5th Avenue without facing legal consequences.
The Federal Government cannot enact a law limiting the ability of State Jurisdiction prosecuting anyone for breaking that state law, to do so would breach the Tenth Amendment.
The Tenth Amendment ordinarily being one dear to the hearts of Republicans, but then so is expediency in matters protecting their own law breakers.