It was never meant to be this way: 2008 was supposed to be a year of peaceful transition, marking the end of the turbulent Bush era and ushering in a new period when relations between the world powers could only improve.

Instead, with four months to go, this year shows all the signs of becoming a turning point in modern history for all the wrong reasons.

True, American democracy has rarely put on such a captivating spectacle as the present race for the White House between John McCain and Barack Obama. With the two running neck and neck in the final straight, much will depend on the three presidential debates in the run-up to election day on November 4. Americans will be looking for the candidate who can rescue the country’s failing economy and tackle the growing crises beyond its shores.

Uppermost is the threat of a new Cold War with Russia, triggered by August’s short but brutal war in Georgia. The newly assertive Kremlin, ostensibly under President Medvedev but in reality controlled by the Prime Minister Vladimir Putin, has made clear that Russian forces will remain in Georgia for the foreseeable future. Moscow is prepared to use economic, diplomatic and even military force to prevent Western expansion into its “near abroad”, as it likes to call the former republics of the Soviet Union. The West was asleep when this crisis erupted on the first day of the Olympics, but is now wide awake and is giving Moscow its complete attention.

This week Dick Cheney, the US Vice-President, will visit Tbilisi to offer his support to the embattled Georgian President Mikhaeil Saakashvili. The issue is likely to dominate discussions at this month’s United Nations General Assembly. The annual meeting of world leaders will give us the first glimpse of the new divisions in global politics. Of particular interest will be nations such as Syria, Venezuela, Belarus and Iran that choose to side with Russia.

America will be pressing its allies to take a tough stand against the Kremlin, but European states, many dependent on Russian energy supplies through the winter, will be more cautious.

Expect an explosive meeting of Nato foreign ministers in December when the alliance must consider whether to invite Georgia and Ukraine into Nato’s membership action plan, the first step to joining the alliance.

Elsewhere, traditional flashpoints, such as the Middle East, are as volatile as ever. This month Ehud Olmert, the Israeli Prime Minister, steps down as leader of the ruling Kadima party over corruption allegations. A furious battle is already under way for the succession with Tzipi Lizni, the Foreign Minister, tipped to succeed and become the first female leader since Golda Meir. The domestic power struggle makes Mr Bush’s pledge to secure an Israeli-Palestinian peace agreement before the end of the year even more remote.

Iraq is also undergoing profound changes, this time for good reasons. The country’s previously restive Anbar province is due to return to Iraqi control soon. General David Petraeus, the commander credited with turning around the security situation, will hand over command to Lieutenant-General Ray Odierno in the middle of the month. The success of the US military surge means that America is likely to conclude an agreement with Baghdad before the end of the year that would bring the steady withdrawal of US combat forces and the likely pull-out of all troops by 2011.

The growing stability in Iraq stands in sharp contrast to the deteriorating security in Afghanistan, where both US presidential candidates are committed to sending thousands more troops to curb increasingly daring raids by the Taleban.

Whatever tactics Nato can devise to defeat the insurgency, Afghanistan’s future is tied to the situation across the border in Pakistan, where the Taleban, al-Qaeda and other militant Islamic groups are growing increasingly powerful. Part of the problem facing the nuclear-armed country is the lack of leadership. Pervez Musharraf, who stepped down as President last month, was the common enemy keeping the coalition together. Now Asif Ali Zardari, Benazir Bhutto’s widower, looks set to become the next president while his former ally Nawaz Sharif will head the Opposition.

Expect another tough leadership battle in November in the French Socialist Party, between Bernard Delanoë, the Mayor of Paris and Ségolène Royal, the failed presidential candidate. President Sarkozy has other challenges. France has focused its EU presidency on salvaging the Lisbon treaty, rejected by Ireland in June’s referendum. That will mean giving incentives to the Irish to hold another ballot next year and join the 24 other EU states that have ratified the treaty.

There are a few bright spots on the horizon. Beijing hopes to follow the success of the Olympics with the Paralympics. Sir Paul McCartney has been invited to perform in Tel Aviv this month, 43 years after Israel barred the Beatles on the ground of an “insufficient artistic level”. And, this week, Turkey and Armenia will try to bury a century of hatred by playing a World Cup football qualifier in Yerevan.