Dante Straziami is a powerful and senior senator (note that the length of his senatorial cloak, which displays his tenure).
At lower levels of the conspiracy, he helps solidify your control of the Senate with his strong 4 influence, and makes that control more worhtwhile with his ability to bump up the Senate’s value. Just be sure you can handle being the scapegoat, because dropping him in at lower elevsl will practically ensure you remain there.
At the upper levels of your conspiracy, he uses his clout to ram laws through the senate to benefit those consituents that support your conspiracy. Business as usual in politics, really.