At various points since the field largely took its current shape in August when Rick Perry entered the race, Gallup polls have shown Perry, Cain, Romney, and now Gingrich as the leader or tied for the lead for the Republican nomination. Earlier this year and late last year, Gallup polls showed Mike Huckabee, Donald Trump, and Sarah Palin -- all of whom eventually declined to run -- leading or tied for the lead.

- Gallup.

And through it all, Romney has stayed steady.