I believe Shiller talks about this in his book Animal Spirits. Markets tend to fluctuate widely even though the fundamentals are not flutuacting that much
The 80's experience in Brazil (and in a lot of other countries) suggests those issues (fiscal problems, hyperinflation, debt defaults) might have an impact on long-term stock returns but they are problably not that significant (after all, they happened and yet corporations continued to deliver strong returns to stockholders).
Certaintly that impact is a fraction of what the market actually does when they happen. Markets will drop 50% in what they should be dropping maybe 10-20%. Then it will correct that overshoot by rallying 130% at some point in the future. What pretty much can't happen is for markets to keep overshooting downward forever, at some point the economic forces driving the market are so strong, stock prices pretty much have to rise (otherwise dividend yields would be huge, M&A would be rampant, companies would buy back themselves with profits etc).
So, in my view/model of how stocks work, to be worried about XYZ and avoid the market is a timing strategy. It can pay off if you do it well (you can then buy back cheaper) but it can burn you badly if you dont do it well (you watch the market rip 50% without you). It certainly it not an investment strategy. An investment strategy is to look at valuations/sentiment and maybe the trend.
But given that politics are so uncertain, to avoid a cheap market (that already had a significant drop) because you think this or that vote wont happen and maybe it will give you a chance to buy a market even more cheaply, it might be even a poor TIMING strategy.