According to the Center on Congress, a politico, or politician, considers both constituency interests and personal judgment when deciding to vote. In the U.S., many politicos are members of Congress.
Before voting takes place, politicos engage in information gathering. U.S. Members of Congress do this through accessing the Congressional Research Service and reading committee reports and letters from other members. These resources serve as the basis for expert opinion.
A politico then proceeds by examining the needs of his constituents. Almost all congressman visit their districts or states multiple times a year to rally support for the next election and analyze public opinion. The Center on Congress notes that congressmen expect only the most passionate of citizens to actively campaign for a certain voting decision. Additionally, congressmen enter office with an ideological viewpoint which they take into consideration as well.
When a politico votes based on his position, it is an example of the trustee model of representation. Experts say the trustee model solves the issue of an uninformed constituency. In contrast, the delegate model of representation limits the politico to only voting based on the mandate given by the represented. The Center on Congress concludes that the factors involved in voting vary between politicos, as the decision making process is often lengthy and complex.