Jim, if you look at the injunctions of many of the OT prophets, they are full of calls for the rulers and people of Israel to be compassionate to the poor, the widows and the orphans. Now,as Baptists, you and I may be more NT-separation-of-church-and-state people than OT-theocracy-types, but there is nevertheless a case to be considered there.
I think what is more interesting is how and why American and British Christians arrive at these differing interpretations of the same Scriptures. I think this is largely because of the different social, political and cultural milieus in which we do that interpretation. I have said before that sometimes ISTM that Christianity in America has more to do with the American Way of Life (TM) than the Bible. That is perhaps a rather unfair comment, and American Christians would be well within their rights to retort that the reason for that is that the American Way of Life (TM) is largely founded and built upon Christian principles and values. I think that both 'pathologies',as it were, work side by side in parallel: America, founded by those seeking to set up their own version of True Religion (TM), developed as a place of rugged individualism and that in turn shaped the forms of Christianity that took deep root there, which tends to be anti-government interference and respectful of the autonomy of the individual and in particular their property rights. In the UK, however, although we had Baptists and other non-conformists, the major expression of Christianity was one of Establishment, and hence we developed over time a perhaps more consensual, collective and corporate approach to politics. (The closest perhaps we got to a more North American expression of 'Christians-in-politics' was in the mid-17th century when the non-conformists ruled the roost, which was an experiment which went rather wrong and ended up ironically threatening private property rights, thus prompting a backlash in favour of the Establishment and property in the 1660s Restoration period.) Despite the respect for private property (don't forget, "an Englishman's home is his castle"!), therefore, politics in England has always been about much more than just the individual, and the rich and propertied have tended to feel a sense of obligation towards those less fortunate than themselves. Add to that the fact that Christians, particularly evangelicals, have been heavily involved in the business of government and social reform, for at least 200 years - Wilberforece and the Clapham Sect abolishing slavery, Shaftesbury abolishing child labour, the founders of the Labour Party being more Methodist than Marxist* etc - and you get a very different relationship between Christians and politics here than in the States.
* Another main point of difference is that all three main parties here have Christian roots: in addition to the origins of the Labour Party referred to above, the Conservatives started off as the Tories who were Anglicans largely, and the Liberal Democrats were formally the the Social Democrats (who split off from Labour in 1981)and the Liberals who were formally the Whigs who were the party of the non-conformists (Baptists, Presbyterians, Congregationalists, etc)
Yours in Christ
Matt