The internal negotiations over the lifting of the cap on University tuition fees among the coalition partners have been fascinating to watch.

Both David Cameron and Nick Clegg are natural “pullers” in the way they behave as negotiators. They are usually prepared to focus on the needs of the other side in order to get a deal done – listening, exploring, disclosing – that is how the coalition deal got done in the first place.

However, in this instance they have needed to “push” their MP’s in order to win the vote permitting a substantial increase in tuition fees. This has been less of a problem for David Cameron (only 6 Tory MP’s voted against the Government yesterday), but it has been a real headache for Nick Clegg, whose party had pledged not to increase tuition fees at the election, and he has had to work extremely hard to get enough of his MP’s to vote in favour of the proposal.

What “push” tactics has Clegg had to use in order to overcome a natural reluctance among Lib Dem MP’s to avoid being seen to renege on their promise to the electorate?

He has used deadline pressure, culminating in a make-or break vote in the Commons on Thursday. This kind of pressure can force people into making decisions they would rather not make.

He has also used “budget buster” tactics, making the argument that he really would love to accommodate his reluctant MP’s, but the public purse just won’t stretch to keeping the tuition fees cap in place. This kind of pressure tactic is very frequent in business deals – how often do you hear the phrase – “We’d love to accept your proposal but unfortunately we just can’t afford it”. In this case the claim has the added force of being true, as the country simply can’t afford to keep subsidising a student population which has more than doubled since the early 1980’s.

He has also, no doubt, used the prospect of a WATNA to try to drag recalcitrant MP’s back into line. A WATNA is a “Worst Alternative To A Negotiated Agreement”. In this case Nick Clegg will have been pointing to a worst alternative in which, if his proposal was not agreed, the Coalition could be fatally undermined, leading to the possibility of another election at a time when the Lib Dems are struggling in the Polls. For a lot of Lib Dem MP’s that will have been a worse prospect than voting in favour of the Government’s tuition fees proposal.

Finally, Nick Clegg has used one clever piece of “pull” behaviour – disclosing his own sadness and regret at having to go back on an election promise in light of an informed understanding of what the country can afford. This kind of admission is rare in politicians who normally go out of their way to mask or deny any U-turns. Sometimes such frank disclosures can have a very disarming effect in neutralising opposition to a deal.

All in all the mixture of push and pull behaviour has (just about) worked. The Government got its majority in Thursday’s vote, and no Lib Dem ministers voted against it. Just over half the Lib Dem MP’s either abstained or voted against it though, so its just as well Nick Clegg put in all that hard work…