Just as investment banks are cutting their growth forecasts for Russia because of a growing likelihood of new U.S. sanctions, Russian legislators are looking for a strong response.

A proposal that could make it illegal to obey the penalties has received preliminary approval from the parliament's lower chamber. It may not be Moscow's final word, but it shows the Russian political elite is leaning toward deeper self-isolation.

The bill, sponsored by the speakers of both chambers of parliament and the leaders of all parliamentary factions, proposes a sentence of up to four years in prison for applying any foreign sanctions in a way that restricts the ability of Russian citizens or entities to perform "ordinary economic operations or deals."