Their best interest is also whatever helps keep them in office. Terrible representatives are typically only secure in their offices if they have the protection of the party. The President has as much power as leader of their party as they get from their actual office. FDR used that to great effect.
Other than Bernie, who are those?
Their best interest is what can make them the most money, which is why they’re legally allowed to do insider training.
Their best interest is also whatever helps keep them in office. Terrible representatives are typically only secure in their offices if they have the protection of the party. The President has as much power as leader of their party as they get from their actual office. FDR used that to great effect.