Dmitry, Even though political ups and downs affect the foreign exchange (FOREX) rates in the very short run, ultimately it's the economic fundamentals that determine the rates. In the short run, I go by the interest rate differentials to gauge the FOREX rates. But, in the long run, the purchasing power parity is the determinant of FOREX rates. As such, I use and measure the implied inflation model to make predictions. As such, there is no ideal USD/RUB rate but there is/are undervalued, overvalued, or fairly valued currencies in FOREX markets.

I did not say to rule out political events affecting the FOREX rates. On the contrary, I said that political events affect the FOREX rates but only in the very short- to short-run. In the long-run (or given enough time) ultimately, it's the economic and financial fundamentals that determine the FOREX rates.

It seems that any deterioration in U.S relations with other countries leads to the fall of the national currency value.

Given the fact that the USD is the most widely held global reserve currency, that is correct most of the time.

As I mentioned previously, I go by "the economic and financial fundamentals as the dominant factors in determining the FOREX rates."

https://www.researchgate.net/post/How_can_the_world_help_Russian_foreign_policy_to_become_less_belligerent_Kak_mir_mozet_pomoc_rossijskoj_vnesnej_politike_stat_menee_voinstvennoj