Scott Walker wasn’t supposed to call an end to his Republican presidential campaign … so early.

Wasn’t the Wisconsin governor at or near the lead in Iowa? Didn’t he appeal to those Christian evangelicals? Isn’t he the guy who stood up to those unions in Wisconsin, which plays well with the GOP base?

Well, then he started talking.

He equated those union workers to the Islamic State.

He then decided it is worth discussing the possibility of building a wall across the nation’s border with Canada.

Then along came Donald Trump, Ben Carson and Carly Fiorina — three political outsiders — to knock the wind out of Walker’s “establishment” message.

The end of Walker’s campaign comes only a week or so after former Texas Gov. Rick Perry’s swan song.

It’s becoming a bit of a guessing game now.

Who’s next? Ex-New York Gov. George Pataki? Former Virginia Gov. Jim Gilmore?

While the media are fixated on polls and whether any of the still-large GOP field is able to reel in Trump, many of the rest of the GOP field are trying to have their voices heard.

Unfortunately for Gov. Walker, those times he actually was heard … he managed to make declarations that exposed him to ridicule.

Let the culling of the field continue.