Where's the proof that Romney is a conservative?

I can understand why some Republicans can support Mitt Romney for the GOP presidential nomination but I can't understand why those same people might believe Romney is a conservative.

Where's the proof that Romney is a conservative? He didn't govern as a conservative when he was governor of Massachusetts. He enacted RomneyCare, which became the inspiration for ObamaCare, and even now continues to defend his failing socialistic program to the bitter end.

Some of the most nonsensical defenses of Romney have come from the otherwise sensible Ann Coulter. Her recent columns assume that Romney has long been a conservative but that he's been concealing this conservatism in order to advance politically. He had to do so in order to win in Massachusetts, she argues.

I'm not convinced.