"As I stood in plain view of this man, later identified as Gates, I asked if he would step out onto the porch and speak with me.
He replied, "No, I will not."
Crowley asked Gates to step outside twice. Once when he (Crowley) arrived at the home & later, after Gates became confrontational inside the home.
Unless you assume that Crowley had planned on arresting Gates at the outset, the request to "step outside" has nothing to do with creating circumstances which would allow for an arrest.
It was Gates' demeanor, once outside the home, that led to his arrest. Not the request that he "step outside".
Here’s the police report. Read the second paragraph of page 2.
http://www.thesmokinggun.com/archive/years/2009/0723092gates1.html
parsy.
And this link will explain why the cop had to maneuver Gates (the idiot) outside so that he could arrest him.
http://www.criminal-law-lawyer-source.com/terms/arrest-warrant.html
parsy.