When Naoto Kan looks back on his year as prime minister of Japan – and it probably won't be long before he is looking back on it – he would well use the term popularized by Britain's Queen Elizabeth after a stressful 12 months and call it his "Annus Horribilis."

That is Latin for horrible year. And no matter how horrible for Queen Elizabeth, she never had to survive a vote of no confidence like Kan did by vaguely promising to resign. Kan tried to keep his resignation open-ended, but many leaders of his Democratic Party of Japan are already busy measuring the curtains of the prime minister's residence.

The next person occupying the prime minister's office may not even be a member of Kan's own party. Ever since the March 11 combined earthquake/tsunami/nuclear disaster, there has been loose talk of a coalition between the two main and possibly smaller parties. Though still unlikely, that possibility is looming larger.

It has gained renewed currency as one means of breaking the parliamentary gridlock and passing necessary legislation to fund the budget and repair the damage wrought by the earthquake. One might think that the two sides might come together to pass legislation obviously needed to relieve suffering, but that might be asking too much of Japan's dysfunctional government.

In any case, parliamentary democracies think in terms of coalitions not bipartisanship. In one scenario, LDP leader Sadakazu Tanigaki assumes the prime minister's position at least temporarily in order to have the Diet pass needed legislation then calls a general election. That the new ministers may hold office for only a few months would hardly be novel in Japan.

Naoto Kan recently passed the one-year-in-office milestone, a dangerous time for Japanese premiers. His four predecessors, Yukio Hatoyama. Taro Aso, Yasuo Fukuda and Shinzo Abe, all held office for one year or less (in Aso's case he resigned after losing the 2009 general election). Kan had hopes of breaking this pattern that has been embarrassing to Japan.

Kan's Annus Horribilis got off to a bad start, and he never really recovered. Within weeks of assuming office on June 4, 2010, the Japanese went to the polls to choose half of the House of Councillors, the upper chamber of Japan's bicameral parliament. Kan's party lost enough seats to hand the chamber over to the opposition, resulting once again into a divided Diet.

The July upper house election was scarcely over before Kan was fighting for his political life in an election for president of the DPJ against his nemesis Ichiro Ozawa. Although he won a comfortable majority among the party rank-and file, he only narrowly carried the party's parliamentary members. The narrowness of that vote would portend trouble throughout the year.

A former party president, Ozawa has been a ball and chain on Kan's leadership. Kan's dilemma is that Ozawa is viewed as corrupt by the general population and a drag on the party in general, but because of his electioneering skills he is popular with the members of parliament, including about 100 freshmen members he personally recruited, groomed and placed in the Diet.

Ozawa was stripped of his party privileges last February after he was indicted on suspicion in an illegal financial transaction. In retaliation many of his supporters did not show up for a vote on the 2011 fiscal budget and 16 openly threatened to leave the party. Kan has never felt strong enough to expel Ozawa.

The recent no-confidence vote may have been submitted by the formal opposition, but its only chance of actually passing had depended on significant numbers of Ozawa followers actually voting against their own government, which or a while seemed very possible. This failed to happen only after Kan's last-minute promise to resign sometime in the near future.

The prime minister spent much of his time between the party election last September and the massive quake in March trying, mostly without success, trying to find some combination of votes that would permit him to pass important spending bills, including the authority to issue bonds that underwrite 40 percent of the budget, against an opposition promising to block any such move to force a new election.

Even now, despite the extraordinary circumstances of what has been called Japan's greatest post-war disaster, the opposition is willing to hold the budget hostage, in a move similar to Republican objections to raising the debt ceiling in the US, unless Kan resigns or perhaps a "grand coalition" government is formed.

The earthquake and subsequent nuclear power plant meltdowns did give Kan a temporary reprieve from relentless opposition in parliament and in his own party and perhaps a chance to demonstrate leadership in a crisis. But while it is difficult to find serious fault with his government's response, it is equally difficult to pinpoint any genuine successes either.

He rather impulsively flew to the stricken Fukushima nuclear power plant complex the day after the earthquake to personally assess the situation, but all it earned him was criticism for getting in the way of the plant operators struggling to contain the nuclear meltdown. When he returned to the earthquake region three weeks later, he was criticized for not reappearing sooner.

When Kan entered office a year ago, he had two main goals. One was to fix the social security system, which like many similar entitlement programs is suffering from an aging workforce, by raising the sales tax from the current 5 percent to 10 percent. Another was to enter into more free trade agreements, an area where Japan is losing ground to regional neighbors such as South Korea.

His authority weakened at first by defeat in the upper house elections and by subsequent events including a no confidence motion, which have delayed any real progress on social security reform, certainly under a Kan administration. Meanwhile, the need to refocus attention on rebuilding the devastated northeast, has swept any real thought to pushing more free-trade zones off of the table, at least for now.