Once the tittle tattle has eased off, and Cable completes his transition from conscience of the people to just another political animal...
It poses an interesting question; Ministers sometimes have to take on a quasi judicial role for which they are expected not to let their political views or standing affect their judgement. This is not easy, and the mark of a good judge is one who can hear inadmissible evidence and not let that evidence influence their judgement.
Sadly, we expect that of politicians. They are not Superman, Superwoman whatever. They are people, driven by a noble cause perhaps but habitually shallow, either from the outset or eventually.
Cable had been entrusted with a decision over a business deal. Whatever the rights or wrongs of speaking under Chatham House rules, off the record, with constituents who deserve a less guarded answer... his role in the BSkyB affair is not that of a politician, so he had no right talking about it. To anybody outside of his role in this decision.
For that alone, he should not hold Ministerial seals of office. The government regulator I am involved with has, as part of the legislation it upholds, a clause where individual inspectors can be prosecuted for revealing information about ongoing enquiries, (especially with regard to handling documents.) I see parallels here.
And here was me thinking "we are all in this together."
That said, other than a general election tomorrow to sort the whole thing out, (which I am not a fan of whilst the economy is still so fragile,) we are lumbered with what we have, and if Cable et al are restraining the more idealogical policies their Tory best mates are pushing, then that could in theory lead to more robust challenge, which can lead to better government.
Mind you, the jury is still out on that one.