Is the Salisbury Convention dead? The idea of it is that the House of Lords should not stand in the way of the government, with its House of Commons majority, delivering the manifesto promises on which it was chosen by the voters. The idea is attributed to Lord Salisbury, who was Conservative leader in the Lords in the 1940s and 1950s, and was developed in particularly after 1945, when Clement Atlee's Labour government, with a huge Commons majority, faced an equally huge, but unelected, Conservative majority in the Lords. So the custom is that, while the Lords can propose amendments in the public interest, it cannot introduce wrecking amendments, and it will not oppose manifesto promises on second reading.
But on what manifesto was the present coalition government elected? There were two manifestos, with plenty of conflicts between them. The government might say that it quickly drew up an agreement, with each party dropping some promises but accepting others from the other side: but the electors never had the chance to vote on this compromise. So what authority should it have?
Already, Labour peers are threatening to tear up the Convention and set themselves free to oppose coalition bills. In so doing, they only hasten their own demise. An opposing majority in an unelected House of Lords might be tolerable if it makes useful amendments and does not block legislation out of partisan spite. If they turn every issue into a party issue, though, people will start asking by what right do these appointed, mostly superannuated ex-politicians dare to interfere? It all increases the pressure for an elected House of Lords.