Former US President Bill Clinton said in his speech to the Democratic Convention nominating Barack Obama for re-election that he always gave a one-word answer when people asked how he had managed to balance the budget during his own second term: Arithmetic.

And I think we can give a similar response in answer to the question why the biggest loser from the recent Legislative Council elections was none of the political parties or individuals vying for office, but rather our very own minister for Constitutional and Mainland Affairs Mr Raymond Tam.

Mr Tam needs to bring forward proposals to provide for democratic election of the Chief Executive in 2017, and the Legislative Council in 2020. Moreover, to achieve the latter he will need to utilise the 2016 LegCo elections as a stepping stone.

The relevant provisions of the Basic Law specify that in order to make the necessary amendments to the laws governing the elections, the government needs to muster a two-thirds majority of all LegCo members.

Given that we now have 70 legislators, that means 47 votes, and Mr Tam hasn’t got them.

In order to get them he is going to have to do a deal with someone, and that will not be easy.

The 2010 reform package, which led to the addition of five extra seats in the geographical constituencies and the creation of five new "super" seats in the Functional Constituency section, could only be passed because the Democratic Party members broke ranks from their fellow pan democrats, acted like statesmen, and reached a mature compromise agreement.

It was the right thing to do, but as so often in life doing the right thing carried a price tag. One of the features of the 2012 results is the decline of the Democratic Party – indeed a drop in support for the pan democrats as a whole at the expense of the pro-establishment camp – and the relative rise of the nihilists in the People Power/League of Social Democrats fringe.

Where then is the incentive for any of the moderate democrats to come to the table again and do another deal with the administration?

Clearly the Democratic Party, still bruised from the pummelling it took this year, is not going to go it alone a second time. Its members will want to have the cover of their fellow democrats in the Civic Party and the Labour Party.

I can think of only one concession the administration could offer which might bring all three parties to the table, and that is a promise to abolish the Functional Constituencies altogether.

Such a package would carry its own risks. The concession needed to secure the extra votes from the pan democratic camp could result in the loss of some of the pro establishment votes among the existing FC representatives.

After all, in no fewer than 16 out of the 30 "not very democratic" FCs the member concerned was returned unopposed this time round. Indeed, many of these constituencies have not seen a serious competition in any election since 1997.

Those 16, plus any other Members out to cause trouble, could also put the 47 threshold at risk.

One way to soften the blow might be to give them one more ride on the gravy train: only significant reform of the FCs in 2016 (hence one last opportunity for re-election) with outright abolition deferred until 2020.

In case any of the stakeholders are contemplating a scenario without any progress at all in 2016, I can only entreat them to think through the consequences.

For the government it would mean a failure to follow through on the Beijing promises to Hong Kong people of steady progress towards full democratisation, with key milestones in 2017 and 2020.

Moderate democratic forces would have shown themselves to be no more effective in the real world than their extremist rivals, who would be sure to make further gains in future elections.

Meanwhile if progress could not be achieved by compromise and common sense there would be a strong temptation for anyone with a grievance to take their supporters onto the streets.

That is not "Hong Kong people ruling Hong Kong". Rather it would mean Hong Kong was becoming ungovernable.

So get out there, Mr Tam, and get those 47 votes. It’s all a matter of Arithmetic.