''The devil is in the detail'' is a well-known idiom that is so often so true.
In the case of the Government's plans to change the Resource Management Act, the idiom applies.
Environment Minister Nick Smith's statements this week are but an outline of what the Government has in store.
Dr Smith outlined 10 areas for change, which he aims to have passed into law by the end of the year.
In general terms, much of what is proposed looks positive.
Adding management of natural hazards seems sensible, recognising urban planning is a welcome addition, prioritising housing affordability sounds all well and good and acknowledging the importance of infrastructure appears constructive.
National planning templates make sense, as long as a fair degree of local autonomy for local variation is allowed for, and plan-making desperately needs speeding up.
And who could argue with encouraging collaborative resolution?
Strengthening national tools and greater weight to property rights both, however, could sound a little ominous.
In each case, the proof is going to be in the details that emerge.
Dr Smith's plan is not just to tinker with the RMA, as has happened often since it became law in 1991, but to make significant changes.
It is important, therefore, neither to write off the proposals nor welcome them without reservations.
It might even be that controversial sections 6 and 7 can be altered to give some weight to economic matters.
What will be required is a balanced, careful approach.
This country has already found out, to its cost, what can happen when regulations are too weak as in the building standards and the leaky homes debacle.
In this instance, the pendulum swung too far, only to be followed by over tightening in the other direction.
Fundamentally, whatever the changes, the Act must still ensure good environmental protection and allow neighbours and the community to continue to have significant say.
Fundamentally, too, there must be some scope for local conditions.
In Queenstown Lakes, for example, the protection of outstanding natural landscapes must remain whatever the pressures for more houses, particularly ''affordable'' homes.
This district is growing fast enough and can afford to discourage some forms of development.
In contrast, many other parts of Otago might well want and need to foster more growth and might need regulations to be a little less strict.
At the same time, changes to the Act should make it easer for, for example, greater housing densities.
This is especially so in Auckland, where the model of urban sprawl is reaching its limits. How much better to encourage more inner-city apartment living or infill housing.
Ironically, the Green Party opposes most changes to the Act, often for good reasons, but at present the Act can be used to delay and frustrate what could be more practical and less environmentally damaging developments.
Dr Smith has made great play of a report which says the Act and environmental regulations add $15,000 to the cost of a new home and $30,000 for each apartment.
Although it would certainly help if this could be reduced, we will have to wait and see whether and how this is possible.
The first stage of change, the Resource Management (Simplifying and Streamlining) Amendment Act, passed in 2009, did not achieve as much as it was claimed it might, and a similarly over-optimistic picture is now being painted.
We are now in the second and most significant stage of change, the part aborted last year when National lost the support of MP Peter Dunne and the Maori Party on this matter and lacked the numbers to push amendments through Parliament.
This time, with 60 seats plus Act's David Seymour, the Government can do so, although it would be wise to continue to endeavour to win backing from Labour and Mr Dunne.
As Dr Smith has said, there will be hundreds of amendments and he expects ''intense discussion'' over them.
That is how it should be.
The RMA, passed in 1991, was pioneering legislation that was never going to be without weakness.
The challenge now is to ''reform'' the Act while maintaining environmental protections as well as a degree of local autonomy.