Here is a simplifying view: In the US there are some people, less than 1% of the voting population, who have a lot of power and control of a lot of money and are looking to the political system to make more money.
This less than 1% do disagree among themselves, and that disagreement is the fundamental source of essentially all the political fighting.
For the other 99+%, there isn't much to fight about.
What the other 99+% want can be summarized in one word -- more. For more detail, they want the two biggies, peace and prosperity. For more, they want "life, liberty, and the pursuit of happiness", financial and emotional security, love, home and family, good health, happy, successful children. There's not a lot to fight about there.
So, again, the fighting is from the less than 1% who want to use their money and power to get more money.
Of course, way more than 1% of the voting population are highly concerned about politics, are fighting, but, sorry, guys, they are foot soldiers, pawns, for the less than 1%.
As an example, let's take one of the issues, say, health care. Glancing at history, US health care has come a long way since the lone country doctor with a one horse carriage. In terms of current US medicine, he was not very good. Point: Health care has changed a lot and is still changing, rapidly. So, what solution we come up with should accommodate such change.
Health care can be really expensive, and we need a solution for that. We need in some sense to level out the costs, make them predictable. Ways have been private medical insurance, health care membership organizations, and government provided health care.
So, here are the main concerns: Private health insurance is too expensive for a major fraction of the population, so those people look to other options. Then for the other options, concerns are quality of care (it might be too cheap and not very good -- loved ones could die), waiting times, and big tax increases. Point: These are all issues, but some examples can show that we should be able to do quite well on all the issues of quality, waiting times, costs, etc., well enough that we should not have much to fight about.
And there has been the issue of private insurance and
"pre-existing" conditions. We can all agree that it would be nice for private insurance companies to ignore such data, conditions. And the richer US states did have laws forcing the insurance companies to so ignore. But maybe now the US is wealthy enough to so ignore for everyone. Hopefully. So, we can all agree or nearly so. Not much to fight about.
So, what is the cause of the the fighting? With some approaches and situations, for less than 1% of the voting population, there is or can be a lot of money involved, or a lot of power and then a lot of money.
My view is that we can go down the list of main political topics and conclude the same -- for 99+% of the voters, there's not much to fight about except some people, less than 1%, want to fight to make money, big money.
But for various policies, operations, programs, etc., it really is possible just to make a mess, to create waste. At least the 99+% can be against the waste!
E.g., for the $trilions W and Obama spent on Gulf War II, was that from (a) people who were in line to make money from the effort or (b) just waste? I'd say, some of (a) but mostly (b). Point: Not all the issues are about the less than 1% seeking money and, instead, there can also be ordinary waste.
Bottom line: The 99% should throttle the less than 1%, settle differences, and get on with life.