I agree with Redleg, and I'm a liberal.

Our 'side' tends to use the 'conservative' label in much the same blunt instrument manner, as a dismissive derogatory akin to baby-eaters and fascists - it's just that conservatives tend to be so much better at condescension and insults.

Liberal has a long and honourable history as a political philosophy, and I wear that badge with pride (even in the current US definition of the term).

It's only perjorative if you are unsure of your ground. The modern-day US Democrats, for example, are so bereft of ideology that they run screaming from the word 'liberal' as if it is a curse. They should stand tall and try to convince the American voter that the liberal way is a good choice. If they can't do that honestly and forthrightly, and bring the people with them, then they have no right to expect power by stealth.