No, immunity from prosecution for politicians is not consistent with the need to uphold privilege, because politicians already think they can get away with everything they want, even without literally having a license to do everything they want. Having prosecutors who are not of the same jurisdiction as the offender deciding whether to prosecute is a way to avoid political conflicts of interest.
No, immunity from prosecution for politicians is not consistent with the need to uphold justice, because politicians know they can get away with committing crime, so they are less likely to act in accordance with the law. With modern technology, an abuse of power by law enforcement used to influence an election is unlikely. Politically-motivated law enforcement would be vetted by the public and is not a significant concern.