Applied to politics, rational choice argues that each category of political actor (e.g. bureaucrats, politicians, voters etc.) are motivated by rational calculations of their personal utility (self-interest) defined in terms of a single, uniform variable. Ratchos in political science define 'utility' for politicians in terms of maximising votes in order to get elected or re-elected (Anthony Downs theorised that politicians act solely in order to attain the income, prestige, and power which come from being in office). Any suggestion that politicians are significantly concerned with societal well-being or the common good, or that they are guided by fundamental ethical precepts, is generally dismissed. Indeed, ratchos have tended to reject concepts like 'public service', the 'public interest', and even 'social justice' either on the grounds that they have little, if any, meaning or relevance.

Of course it is possible to widen the definition of 'utility' to mean any type of motivation, including acting on the basis of principle, altruism, the public interest etc. etc. but in this case, the theory risks all potential significance by becoming unfalsifiable.
It would the equivalent of arguing that people act for a motive. Moreover, it would negate the central tenet of rational choice theory is that all human behaviour is dominated by self-interest.

In my view, ratcho theory cannot explain Noda's behaviour because he was acting on the basis of several different motivations (which violates the 'single uniform variable' requirement) and by both personal self-interest and considerations of the collective good (which violates the self-interest requirement): i.e. 1.
he was convinced that raising the consumption tax was the right thing to do for the economy/the budget bottom line (principle) - no matter that he had been originally convinced by the MOF - he was still convinced; 2. he wanted to demonstrate strong and decisive policy leadership to his party and to the wider national electorate; and 3. he wanted to go down in history as the politician who raised the consumption tax (a Kan-like vanity). You might be able to bend the latter two motivations into some kind of 'maximising votes' personal utility maximising explanation if you were a ratcho.

Aurelia George Mulgan