Don't do that. Diversify, yes. Betting against the US indices? The history of bankruptcy is written with the tears of men who bet against stock market indices.
And keep some money in the US as a hedge against global meltdown. I know that sounds weird, but consider the experience of the 2008 financial crisis. It started in the US, and its epicenter was the US. And yet it was foreign markets whose stocks got hit the worst. How?
In a panic, there's a flight to "quality" which has historically been dollar denominated assets, and in particular Treasuries. Now, we should ask -- are US assets still "quality"? The answer is "what do the markets think?" which is in essence a collective action problem.
I've modeled a US debt default, and even in that case there are two multiple, stable equilibria: either investors panic and flee US assets, which will cause a fire sale of unimaginable proportions; or they buy dollars despite the default because they think other investors will do the same. These days "quality" means something different than it did, say, 20 years ago. It's about charts now, and the US dollar has the best chart. But it's only about charts until it's not.
Don't try to time the market.