Politics is manifestly not about the public good - not even with compromises.
It's mostly about a few unpleasant - sometimes charismatic - individuals pursuing power for their own personal benefit, and covertly that of their funders and sponsors.
Science has nothing to contribute to this, because the entire business is so hopelessly toxic and corrupt that rational debate about policy doesn't even get to first base.
If you want rational policy you don't want politics. It's perfectly possible you don't even want democracy.
What you want is administration - a very different process where mature competent executives and managers who do not have Dark Triad personality traits make intelligent, informed, and compassionate decisions in the public interest based on evidence, expert guidance, and their own good instincts. And their power is strictly limited to the lightest possible enforcement required to do the job.
No country has even been run like this, but a few have managed to operate like this in selected subfields.
Which is basically inhuman. For an administration of any sort, you need a selection process and the selection process will then be gamed by exactly the people who seek power.
Which is why we have large bodies of political representatives: people will not stop seeking to acquire power and act in their interests and the interests of their backers, but they will be counteracted by people doing exactly the same but pursuing different ends. That’s a very human thing.
Based on what I have seen, most politicians genuinely believe they are working for the common good. Their understanding of what the common good is obviously varies.
In a system like that, politics is mostly about playing the long game. You build a personal brand that gets you elected and re-elected and gives you influence within your party. You build and maintain your networks, you collect political capital by supporting others' goals, and you spend the capital to advance your own goals. You try to find a balance between short-term and long-term goals, because your opponents today may be your allies tomorrow, and you don't want to alienate them by playing too hard.
Unpleasant and toxic people may sometimes survive in politics. They are rarely successful, because politics is all about people skills, at least in the system I know of. (Such people are more common in administrative positions, because their status is more secure in a meritocratic hierarchy.) People focused on specific topics often also have a hard time in politics, because they have a tendency of becoming unpleasant when things don't go their way in the niche they are interested in.
The public image of politics can be toxic, because the current publicity game requires it. The same politicians often appear quite different behind closed doors, where they are allowed to speak off the record.
All of the other scientists and researchers see this and adjust their own behavior and areas of study to avoid being mobbed.
I have had to become increasingly cautious and wary of trusting all published science, especially that in social areas now.
It isn't rational that you love your wife more than other women. Why constrain yourself to such rules for policies?
Is dying for your freedom rational? Investing in symbolic architecture? Skydiving could be seen as fundamentally irrational. Some still do it.
All depends on how exactly you define rationality.
Overall it might be prudent to value rational arguments, I complete agree with that.
edit:
> It isn't rational that you love your wife more than other women. Why constrain yourself [...]
Reading it again, this can transport something different than the point I tried to make...
It is a preference and that is what form the basis of interests.
> dying for your freedom Is somewhat different, it's already the execution of a policy (fight) for a preference. And I think it can be perfectly reasonable outcome as it's not even hard to find chapters in History during which conditions made it the only acceptable choice
What problem are we solving, what is or isn't a problem, what constitutes a better outcome, and what types of policies are allowable may be informed by science but are often (and often appropriately or at least inevitably) decided by culture, law, art, force majeure, etc.
It would also be good if all those models were used as basis to discuss divergent interests and that politics would remain politics as a tool to select policies that maximize a majority (but not everyone's) best interests.
I feel, instead the issue is that it's become unacceptable to disclose what are someone's own best interests and to defend those.
Instead everyone produce fallacious models that show that their prefered policy is in everyone's best interests.