Do political parties focus on influencing policies

No, they don't.

Explanation:

Political parties generally only focused on maintaining total votes to hold or improve their position. Influencing policies are most commonly done by Political Action Committee (PAC).

PAC is a group that commonly consist of people from the private sectors. (such as activists, business representative, etc). PAC usually funded several political candidates in order to influence the creation of a certain policy. The policies supported by PAC generally only benefited the members of the PAC rather than the citizens as a whole.

frederick william of brandenburg-prussia trained his son, frederick, to be a hardy soldier. but frederick disliked rifle shooting and horseback riding. unlike his father, he was interested in french literature. he enjoyed poetry and music and, like some others of the enlightenment, he scoffed at religion. his father thought him soft, frivolous and unmindful of his duties. and when frederick refused to put his signature on a right to succession, for a few moments his father strangled him.

after the roman empire, the catholic church began to unify by taking on many duties of a government.