Given the politics of the upcoming election this November, I doubt that the United States would see martial law (at least on a national level). Martial law, even more than the Federal- and State-mandated laws presently in place to slow down the infection rate, would damage the economy severely; a bad economy is usually a bad thing for a sitting President during an election.
Also, given the bad blood between the President and the governors of the powerhouse states like New York and California, any attempt to impose a martial law scenario -- with the exception of Federalizing the states' National Guard -- would be ignored by most of the lower level governments (states, counties, cities, etc.)
