I'm reading The Hugo Young Papers, whose main feature thus far has been to make you realise how far the terms of political discourse have been shifted to the libertarian right since Young started his journalistic career: the idea of the Tories fighting an election over their right to impose a national incomes policy, as Heath did in '74, is unimaginable now. However, I've now just reached the early eighties and the formation of the SDP and then the Alliance. This is from the interview with Richard Holme in January 1982, who was later to be Lib Dem spokesman in the House of Lords but had then just finished a stint as President of the Liberals. Young asks about the prospect of the Alliance going into coalition with the Tories after the next election and, crucially, how to extract proportional representation from such an arrangement; "how to prevent getting a pledge to PR out of the Tory leader, and then this being ditched by Tory MPs - meanwhile the Alliance being locked into the government and looking stupid":
[G]ive support on the back benches for, say, eighteen months: which would mean that the Alliance would bring down the government, not itself be brought down by Tory backbenchers. This would put the government's survival on their commitment to PR being pushed through the HC - hence a much better tactic than joining the government on a condition not fulfilled.