The attack is being made by some Tory supporters, and may be in the near future by the party proper, that the Lib Dems are soft on crime. It's a traditional attack that is rooted in the Lib Dem's penchant for penal reform and modern techniques of dealing with crime such a restorative justice.
Is it fair to say they are soft, therefore, on crime in this 2010 General Election? Let's see... (You can find all of this information, unless otherwise stated, in the three party manifestos: Labour, Tory, Lib Dem)
3000 more police (actual Lib Dem policy is 10,000 though no doubt this figure is less due to the current economic situation). Tories and Labour currently don't want to offer any more police. This will be backed up by the same sort of measures that the Tories and Labour no doubt wish to employ to get police out of the office and back onto the beat.
Then there's the policy to have elected police authorities. Surely nothing is stronger in terms of message to our police than to say the people will have more say in how they're run? I happen to be really unsure about this policy, but it is at least significantly better than the easily abusable "elected police chiefs" policy of the Tories, where a concerted effort by a fringe extremist group could see police forces hijacked for nefarious means. Labour are, as always, happy to dictate rather than converse.
On drugs the Lib Dems don't differ from either Tories or Labour in wanting to switch the focus of drug related crime punishment to rehabilitation. The difference is that they also wish to have advice provided by an independent scientific body, not tampered with like Labour currently do, and as the Tories support Labour in doing, with their advisory council.
Lib Dems do want to stop building new prisons to save money, unlike the other two parties. Lib Dems would prefer that people sentenced to 6-month to one year sentences aren't automatically sent to jail. those short sentences would still be an option where necessary but where not they can do community service, or other such punishment as reasonably decided by the local community and victims of their petty crimes.
What about the others? Labour are happy to continue imprisoning more and more people despite the high re-offending rate. Perhaps most interestingly the Tories own Ian Duncan Smith agrees with the Lib Dem policy and wants short term prison sentences to be abolished, a step further even than the situation the Lib Dems are calling for (though on a smaller sentence timescale).
Given the right circumstances the Tories will enact almost exactly the same policy the Lib Dems are calling for right now!
Is this the stance of a party that is soft on crime, or a party that is more intent on prevention than punishment? To me it doesn't appear that there is an awful lot that the three parties would do different on crime, except that Lib Dems would better fund our police and apply a new (and arguably better) strategies.