Re: Slippery slope; And not the fun kind
Liberty vs. Authoritarianism is a completely orthogonal axis to political (really economic) left-right. Plenty of authoritarians all over the political axis (it's pretty much a requirement to want to be in parliament, isn't it?).
I am quite far-liberty, but pretty centrist on the UK left-right spectrum (mid-left when viewed from the US, of course).