If you want someone to agree to do something that seems on the face of it to be against their interests then you need to talk to them. You may be able to require them to do what you want temporarily through force or the application of the law, or some other exertion of bargaining power, but the exercise of power does not win over people’s hearts and minds, so they will have no commitment to your desired outcome.
A better way for the process to have worked in relation to public sector cuts might have been for the government to have talked to the relevant Unions before it published its targets for cuts. That way it could have effectively had the Unions own the problem too. It would also have enabled the Government to have listened to Union needs and perhaps found elegant ways of achieving cuts whilst meeting Union concerns.
In publishing its targets first the Government was well-intentioned, and no doubt its perceived tough handling of the need for cuts has impressed financial institutions and avoided a Greece-style melt-down. However, dealing with the issue this way round has effectively foreclosed negotiations, and soured the climate because the Unions feel disenfranchised from the process and under-valued. Hence the wave of strikes.
Instead of criticising the Unions, one sensible way to deal with this would be for the Government to signal an attempt to re-set the climate by saying that whilst it remains generally committed to its goals of reducing public expenditure it is open to collaboration with Public sector representatives as to how this is addressed, and welcomes their input. Showing the Unions that they are valued in the process would reduce the temperature a little, enable constructive dialogue to start, and help the Government share the very real problem of the need for cuts with the parties with whom it is negotiating. It would have been better to have started that process before Christmas, and before the cuts were announced, but it is not too late to start it now.