What a difficult question raised by the posts below. What counts as "political"? What kind of a problem is "the problem"?
Let me suggest that, if by "political" we mean political institutions and by "problem" we mean budget deficits, ineffectiveness and rent-seeking, Persson and Tabellini provide the inevitable starting point (and let me stress starting point) for the discussion: parliamentary regimes with proportional electoral systems (such as ours) generate more government spending and deficits, larger counter-cyclical responses in spending, lower ability to scale down spending during economic upturns, and greater spending in election years. If this is not a familiar picture, I don't know what is.
Furthermore, details in the electoral system also seem to matter for other sorts of "problems". (Perceptions of) government ineffectiveness and corruption are higher in systems where no form of direct accountability of MP's is possible, i.e., in purely list-based proportional systems (although size of districts have the opposite effects, suggesting that low barriers to entry combined with means to make MP's directly accountable would the best solution). I'm sure Paulo Trigo Pereira will have more to say about this.
Could this be "the political problem"? In a sense, it seems "too easy" (just change the rules and outcomes will change), with little attention to other sorts of "institutions" (for example, the fact that the unionization rate in Portugal is below 20% while it is above 60% in Sweden certainly has to make some difference for what kind of policies are set, who they benefit and what kind of credible commitments can be reached). But it's a starting point for discussion.