The US-Russia summit meeting next week is seen as more critical following the sudden dismissal of Mr Sergei Kiryenko and his replacement by Mr Viktor Chernomyrdin.
Even before President Yeltsin's purge of his Cabinet, there were fears here about President Clinton travelling to Moscow at this time. The fact that both leaders are beset with domestic problems and the deepening Russian economic crisis were not seen as good omens for a successful meeting - their first since March last year.
Then last week, Mr Yeltsin irritated the US by his outspoken criticism of the cruise missile strikes against terrorist training camps in Afghanistan and an alleged chemical weapons plant in Sudan. Mr Yeltsin complained that he had not been consulted
Now the new political crisis in Russia has thrown further uncertainty over the outcome of the planned summit on September 1st.
The White House insists that the summit is going ahead in spite of some calls for it to be postponed. The press secretary, Mr Mike McCurry, said yesterday that in US-Russia relations "politics matter more than personalities". Mr Clinton, who is on holiday on Martha's Vineyard was briefed on the political and economic situation in Russia by his national security adviser, Mr Sandy Berger. It is not ruled out that the two leaders may speak on the telephone soon.
The last phone call was on August 14th when the Russian economy was seen as on the verge of collapse.
The return of Mr Chernomyrdin as head of government is good news for Vice-President Al Gore who had built up a warm relationship with him during his previous term as prime minister. It is significant that Mr Gore spoke to Mr Chernomyrdin following his new appointment.
The two men discussed the economic crisis and Mr Gore emphasised the urgency of pressing ahead with the planned economic reforms and of restoring the confidence of the monetary markets. There is dismay here that the $22.6 billion (£16 billion) International Monetary Fund rescue package has apparently failed to restore economic stability. It is only a month since the first tranche of $4.8 billion in loans was paid over to Russia.
The political crisis over the sacking of the Kiryenko government has complicated the plans for the Moscow summit. Originally, Mr Clinton did not want to hold the summit until the Duma, or Russian parliament, ratified the Start-2 nuclear weapons disarmament treaty. But the Duma was refusing to do this because of its discontent with Mr Yeltsin.
Mr Clinton decided to go ahead with the summit in the hope that he would receive a pledge that the Duma would ratify the treaty and open the way to negotiations on a Start-3 treaty. Now the Duma has voted in favour of Mr Yeltsin stepping down and has threatened to reject the Start-2 treaty.
Mr Zbigniew Brzezinski, former national security adviser to president Carter, has called on Mr Clinton to postpone next week's summit. "There is no point for a bleeding President to be visiting a sick and unstable President," Mr Brzezinski told the New York Times.
He said it was clear that Mr Yeltsin "is passing from the scene" and he urged the US Administration "to reach out and establish dialogue with other leaders". These include the Mayor of Moscow, Mr Yuri Luzhkov; Gen Alexander Lebed, now Governor of Siberia, and the Communist Party leader, Mr Gennadi Zyuganov.
US officials say Mr Clinton intends to meet these opposition political figures after his summit with Mr Yeltsin.
Mr Anders Aslund, a former economic adviser to the Russian government, and now with the Carnegie Endowment in Washington, called Mr Yeltsin's latest move a disaster. "It means Yeltsin is finished, it makes him look like a puppet and the Russians can't stand weak leaders," Mr Aslund said. "This really puts Clinton in an awful situation. You don't want to go to a country where there is so much uncertainty."