Yes, elected officials should also serve outside interests while they are in office, because a lot of times, people are not paid enough to be a politician that they can give up their other interests. Also, some politicians are not reelected. They need to keep their careers going so that they can feed their families after their time in office.
Elected officials should also serve outside interests while they are in office. They should be allowed to do anything that they want to do while they are in office. I do not think their life choices should be affected just because of the job that they hold. They had a life and interests before they came into the office and should continue to serve those interests.
Elected officials shouldn't serve outside interests during their terms in office. Doing so is a direct violation of the oath they take to serve their constitutents' interests. Without a doubt, serving outside interests is what has ruined the American political system and harmed American citizens in countless ways over the years.
George Washington warned the US, in his farewell address, to beware of outside influence. While he was speaking specifically of foreigners interfering in US domestic and foreign policy, the same advice holds about politicians today. Too many decisions are made today based on the whims of people with the ability to be heard.
Elected officials should serve their constituents when they are in office and no one else. To do otherwise is a conflict of interest and it might possibly be illegal also. Officials can be punished for corruption if they are caught misappropriating funds or using government resources for personal and improper use.