First off, to all those who thing that the markets are rational - study a little economic theory and practice. They are far from rational.
Second, Russia (Putin) is willing to cut off his nose to spite his face (ie: sell off all dollars and bonds). If he thinks it will get him what he wants. If you think otherwise, you are sadly mistaken.
Third, a couple of years back Putin ordered all oligarchs and similar to get rid of their dollars and unwind western investments. If anyone lost money or loses money from economic sanctions, Putin will just shrug his shoulders, he warned them, Putin plays the long game, never forget that.
Fourth, do not think Putin is stupid. Megalomaniac perhaps, but certainly not stupid. He knows exactly what he is doing. He might misjudge things, make a mistake somewhere, but you can be sure he has carefully laid his plans and has been doing so for a long time.
Fifth, Russia, Iran and China are having talks about moving to a new petro-Rouble as the currency of trade (for oil/gas) in order to move away from the dollar. Russia wants to get away from the dollar, just like many countries would like to, but simply cannot afford to or simply wouldn't find trade partners for an alternate currency. If this happens, it could have a major impact on the dollar worldwide (yes, could also be negative effects for Russia and China, but see my second point).
Sixth, those who are saying if X (eg: Russia sells off dollars) happens then Y (eg: will be good for US) do not understand if it was that simple, then why wouldn't the US already do those things? And why are those people not multi-millionaires themselves if they understand how well the financial markets works? Perhaps because those who control the US economy do not want that to happen, either for their own nefarious reasons or because it would be bad for the US economy.
I'm not saying I know what will happen either. I'm as much in the dark as most people. I'm just a westerner who lives in Russia so i understand the people on both sides and get to see and read both sides' propaganda. Personally i think both sides are being idiots and the people on all sides are being badly manipulated and used by those with vested interests (hey ho, well, that's usual anyway).