THE SNP cruised to an overwhelming victory in the fifth Scottish Parliament election since devolution. By any standards, winning 63 out of 129 seats, including a record tally of 59 constituencies was an astounding achievement.

Nicola Sturgeon said as much in her post-election statement, delivered from the steps of Bute House, a few hours after the last votes were counted.

Her victory was "historic" and "emphatic," she said. It gave her personally and her party a powerful mandate to deliver on its election pledges.

Ms Sturgeon did not labour this point to rub away any tinges of disappointment at failing to go two seats better and secure an overall majority, though to sleep-deprived SNP staffers that might have been how it felt.

Rather, her words were a carefully weighed challenge to the opposition parties whose support she will now rely upon to fulfil a whole host of manifesto pledges.

"Don't you dare defy me," she was telling them, "Or the voters will be down on you like a ton of bricks."

This election changed not very much and almost everything.

Ms Sturgeon will become First Minister again and her party continues to dominate Scottish politics.

Yet the absence of a majority raises hundreds of questions about the next five years that less than 12 hours before Ms Sturgeon spoke, had received no serious consideration.

From now on, deal-making and horse-trading will be the stuff of Holyrood politics.

Where will Ms Sturgeon look for support? And what compromises will she have to make?

SNP spin doctors are making light of the situation pointing out, quite reasonably, that Alex Salmond's minority government survived and usually thrived with only 47 MSPs between 2007 and 2011.

But that doesn't mean it always got what it wanted.

As Mr Salmond learned, budget deals were inevitable and always the sharpest focus of the Holyrood horse-trading.

The Conservatives, who forged an unwritten alliance with the SNP, secured the pledge of an extra 1,000 police officers on the beat and cash for town centre regeneration in return for backing John Swinney's annual spending plans.

And while he could usually do a deal with Annabel Goldie, Mr Swinney also sought support from the Greens, whose Climate Challenge Fund has poured tens of millions of pounds into environmentally-friendly community schemes.

The next five budgets will be no different. Indeed, the deal-making will become even more interesting – and potentially more difficult – because the budget is about to become the real thing, not just a spending plan but a balancing act involving tax and spending.

What will happen when the process starts in the autumn?

On paper, the SNP and Tory income tax plans are close enough to imagine a deal being done.

But, as Ms Sturgeon hinted, she would prefer not to rely on Conservative support.

And the same might go for the Tories, who spent much of the past six weeks warning the SNP would make Scotland the highest taxed part of the UK.

But a deal with Labour, the LibDems or the Greens could prove equally difficult. Ms Sturgeon denounced their call to protect public services by increasing income tax, just as they accused her of failing to challenge austerity by sticking so closely to George Osborne's plans.

A deal will be done – it always is, eventually – but at what price?

And what of the SNP's other plans? None of the other parties support the SNP's plan to cut air passenger duty, the tax on flights. Ms Sturgeon's plans for testing in schools is another potential flashpoint.

Then there is the question of a second independence referendum.

The Greens are very much the black sheep of the Yes family. A second independence referendum is not the top priority for a party where views straddle strong nationalism, federalism and even unionism. They will be more interested in stopping the SNP from allowing fracking and coming up with the kind of radical land reform Ms Sturgeon promised but has not – so far – delivered.

Part of the art of minority government, as Mr Salmond also discovered, is not rushing headlong into needless defeats.

He simply shelved plans for which he knew had insufficient support, such the local income tax. What policies might Ms Sturgeon have to drop?

For weeks we've been told this was the most boring Holyrood election ever. In fact, it's been the most interesting.