The resignation  last week of Japan's prime minister Yukio Hatoyama was greeted with a grim sense of inevitability by the Japanese public, which has grown used to a rapid turnover in the country's top office.
Hatoyama's successor, Naoto Kan , is Japan's sixth prime minister in less than four years. But the latest resignation has particular resonance for politicians in Britain. Hatoyama led a coalition government comprising his own centrist Democratic Party of Japan (DPJ), along with the smaller left-wing Japan Social Democratic Party (SDP).
Although Hatoyama's resignation came largely as a result of his own blunders, the final shove was provided by his coalition partner, the SDP leader, Mizuho Fukushima. Hatoyama's nine months in office were dogged by scandal, indecision and missed opportunities, but he was finally forced out over his failure to fulfil an election promise  to move the controversial US Futenma marine base, currently located on the island of Okinawa.
His reversal on Futenma was seen by the public as symbolic of a broader inability to deliver on critical issues. When he came to power last August, public support for Hatoyama and his government stood at an astonishing 75 per cent; by the time he resigned, it had fallen to 19 per cent.
Hatoyama's failure over Futenma put pressure on his party's already fraught coalition with the SDP, which represents what remains of Japan's socialist electorate. Opposition to the Japan-US security alliance is a central pillar of their pacifist platform, so, not surprisingly, the SDP's Fukushima refused to support Hatoyama's decision to revert to the status quo and allow the US military to remain at Futenma.
The prime minister was thus forced to dismiss her from her post as minister for consumer affairs. The rest of the SDP swiftly followed  their leader in leaving the coalition.
Within Britain's coalition government, David Cameron and Nick Clegg claim to have come to an "agree to disagree" arrangement over replacing Trident. But defence-related issues could easily open up divisions at Westminster similar to those that have occurred in Japan.
There are other similarities between the governments. In Japan, as in Britain, the coalition partners garner electoral support in conflicting ways. Elections for Japan's House of Representatives, the more powerful of its two chambers of parliament, are based on a mixture of proportional and single-member seats. The majority of DPJ MPs are elected in the single-member category, so the party must maintain a centrist stance in order to attract a wide variety of voters from as many constituencies as possible.
The SDP finds itself in the opposite position. The number of its members is in single digits, with more than half elected from proportional lists. The party's survival depends on its reputation as a progressive alternative to the two main parties.
Central to this aim is the SDP's unique commitment to reducing the presence of the US military in Japan and retaining the country's pacifist constitution.
Principle or pragmatism?
While the British Liberal Democrats enjoy wider electoral support than the Japanese SDP, their positions are in some ways similar. The majority of partisan Liberal Democrats -- those who vote for the party out of conviction, and not tactically or in protest -- are drawn to what they consider a more challenging agenda than the one offered by Labour or the Conservatives.
Like Japan's SDP, the Lib Dems will be punished by their core supporters if they are seen to compromise on their principles and election promises.
With elections  for Japan's upper house around the corner in July, Fukushima's options were either to walk or to face the wrath of SDP voters at the polls. She orchestrated her own dismissal rather than be seen to support the DPJ over the Futenma controversy.
Surely it will not be long before Nick Clegg faces a similar dilemma. Perhaps the moment has already passed; joining a Conservative-led coalition in the first place was a slap in the face to many Liberal Democrat voters.
A departure from government on principle before the next election might mitigate the electoral damage to the Lib Dems. Both Clegg and Cameron should watch developments in Japan with interest.
Dr Tina Burrett is assistant professor of international relations at Tokyo's Temple University .