Sweet column: Coach Robinson Iowa roadtrip for brother-in-law Obama.

DES MOINES, Iowa — Craig Robinson was on surrogate duty for brother-in-law Barack Obama at the Polk County Democrats fall dinner Friday, auctioning off a lunch with his sister Michelle to benefit the local party.

A man asked who would pick up the meal tab. “If I know my sister, she is not,” quipped Robinson. The lunch sold for $400.

Robinson, the tallest man in the hall, is the men’s basketball coach at Brown University in Rhode Island and, like his sister — they bear a striking resemblance — a product of Chicago’s South Side.

When Michelle was engaged to Obama, she asked her brother, older by 16 months, to invite Obama to play ball with him. Obama passed the test; he was “confident without being cocky,” Robinson told me.

A basketball star at Princeton, Robinson was an assistant coach at Northwestern and the Illinois Institute of Technology. Along the way, he picked up an MBA at the University of Chicago.

Robinson decided his calling was on the court after years as an investment banker in Chicago during the 1990s.

Now, with Obama in a presidential campaign, Robinson has been increasingly pressed into duty as a proxy.

“I do whatever they ask me to do. And that would be from going to fund-raisers to coming out to events like this,” Robinson said.

When he hit the stage a few minutes later, he started with an unusual disclaimer. “Anything I say is mine and mine alone,” making clear he was not speaking for Brown.

Surrogates play major roles because candidates can’t be everywhere. Every campaign has surrogate scheduling departments. Michelle Obama is the most important surrogate on the Obama team.

Robinson has done events in Boston; Providence, R.I.; Charleston, S.C.; Illinois; New Hampshire — where he appeared in a three-on-three Obama campaign hoops tournament — and now Iowa.

According to an Obama campaign tally, to date surrogates have made 102 trips across the nation since February. They are most frequently deployed to Iowa and the other early voting states.

Former Sen. Tom Daschle (D-S.D.) was dispatched on eight trips for Obama; Rep. Jan Schakowsky (D-Ill.) on seven swings, and Sen. Dick Durbin (D-Ill.) on five.

Actor Forest Whitaker also campaigned in Iowa earlier this month.

After Robinson finished his duties with the Polk Democrats, he had a second mission: sealing support for Obama with several Iowa Democrats over a small dinner at Centro’s, a restaurant downtown.

That capped a long day. To make it work, Robinson called a team practice at 5 a.m. with another session set for Saturday night.

The team does not mind the swing shifts. Said Robinson, “The players are big fans of Barack.”