Was Jan 6 a protest of the government or an insurrection? Can Russians vote or are elections a sham? Do the majority of Russians believe they live in a democracy if they’re afraid of whose conducting the polling (or the MAGA non response to polling)? Those are values question that require you to have an agreement on reality.

> You can even do local predictions if both can agree, such as "will the combined incomes of my family be higher or lower in 4 years time?" as low coupling proxies for gdp

Your personal income has absolutely no predictive value on gdp. It’s more predictive of whether you personally made successful bets or even if you’re better at sucking up to the current power structure. It tells you nothing about population level metrics if you have no way of conducting reliable population level surveys. For example Donald Trump’s personal net worth sky rocketed under Biden because he won the election while as the leader of the opposition to the democrats was looking at jail time and whether that was legitimate or not depends on which political lens you look through it.

> If they affect your life they can be observed.

Ah, but if either side distrusts the other about whether the observation made is truthfully reported, how do you solve that? It requires some amount of trust and right now there’s a very clear divide there.