The electorate may have delivered its verdict on WorkChoices, but the issue clearly isn’t going away just yet. The Rudd government has to frame its changes and then pilot them through a hostile Senate, where the opposition claims its own mandate.

As Tony Abbott said yesterday, “The elected Opposition is no less entitled than the elected Government to exercise its political judgment and to try to keep its election commitments.”

Abbott is quite right. The Senate has a key place in the constitutional framework, and its members represent the people just as much as their counterparts in the House of Reps. Indeed, their democratic credentials are often stronger – Labor’s Senate representation is much closer to its share of the vote that is its representation in the lower house.

No doubt blocking the repeal of WorkChoices would be politically disastrous for the Coalition. But that tactical judgement shouldn’t lead it to accept extravagant claims about Rudd’s “mandate”.

A mandate can provide a justification for things that a government does in accordance with its election commitments. When asked “How dare you implement such a heartless policy!” it may respond (more or less convincingly), “We promised that this was what we’d do, so people have no right to complain. We’ve got a mandate.”

The same notion also provides justification for individual MPs. “How could you vote for that bill?” “I’ve got a mandate.” But the idea that it could oblige legislators to vote for measures they did not support, and indeed specifically promised to oppose, could only be held by someone who had completely abandoned any idea of the separation of powers.

Abbott, however, is being disingenuous when he resists such claims now, since that is exactly the doctrine the Howard government advanced in its earlier days, when it faced Senate opposition to such measures as the GST and the sale of Telstra.

Then, the Coalition strenuously denied that the opposition had its own mandate. Its view was that senators should “respect” the mandate by passing measures they had been elected to resist: in other words, that voters’ instructions to the executive government were somehow binding on opposition legislators.

Kevin Rudd can hardly be blamed if he polishes that doctrine now for his own use. But he shouldn’t be allowed to get away with it.