What are all political parties trying to do?

in short, all political parties are trying to gain power.

Explanation:

Each of the different political parties seeks to gain power, so that their ideologies and opinions can be at the forefront of society. They all hope to be able to put their systems, theories, and ideas into practice

whose power in the senate is equal to the power of the speaker of the house?

i believe it would influence their own way of understanding things. it shall be a foundation where they can draw or start an argument.   historians are also  scientists that  have their tools of analysis and expertise to unlock a variety of difficulties such as relationships of man, origin, politics, economy, and culture. based on facts and understanding on these areas, they may shade light to extract ideas and develop options to validate a hypothesis or debunk it.