Sen. Marco Rubio (R-Fla.), center, photographed with his son, Anthony, left, and father, Mario, on April 27, 2010, the day he signed documents officially qualifying him as a candidate for the U.S. Senate. (Joe Raedlec /GETTY IMAGES)

The decision, he said, speaks to his daily struggle with balancing a swift ascension in national politics with being the father to four young children. The conflict is cited several times in his new volume, “An American Son,” which hit bookshelves this week. o

On Thursday, in the midst of a week-long promotional tour, Rubio met with a group of reporters and spent most of his time discussing the nuances of his position on immigration reform and defending Romney’s statements on the issue.

But at the end, Rubio was asked to address why his book so frequently discusses the guilt associated with his work/life balance and how his Senate career pulls him away from his wife, Jeanette, and their kids.

Having appeared mostly animated and at ease during the breakfast, Rubio’s expression suddenly turned more serious. Here was a chance for him to offer a rare, dad-oriented perspective to the work-life-balance debate that is so often dominated by women--most recently by Anne-Marie Slaughter, former top policy aide to Secretary of State Hillary Rodham Clinton .

“I worry about it, and I think one of the things I wanted to put in the book is that concern,” Rubio said at the breakfast hosted by the Christian Science Monitor.

He then recounted to reporters a story that is included at the end of his book.

“I was in the Senate one day and [Sen. Patrick Leahy (D-Vt.)] comes up to me and says, ‘How are you doing?’ It was just small talk. I don’t know why I answered him seriously, but I said, ‘I’m worried about my kids at this thing this weekend and I’m not going to make it.’”

Rubio said that Leahy recounted to him how, as a forty-something senator in the 1970s, President Gerald R. Ford had invited him to a White House event that conflicted with an appointment involving his children. Leahy said he turned down Ford’s invitation.

“He said 30, 40 years later he doesn’t even remember what the event was, but his kids will never forget the day that he chose them over the president,” Rubio said.

“I use that example, because I had an opportunity earlier this year to go to Africa. It was going to be a pretty good trip. … But my kids had all kinds of stuff going on. My daughters, my son had just started flag football, they needed their parents at home. And I had to make a decision. We were packed. We were driving to the airport when I said , you know what, we’re not going. And I’ll never forget the look on my kids’ face when their dad showed up and picked them up at school. They thought I was in Africa — in a kid’s mind you get there in 10 minutes. I don’t know if I would have remembered that trip had I not put it in the book, but my kids will never forget the day I picked them over Africa and picked them up to take them home.”

“It’s the same thing right now,” Rubio added. “I’ve been on the road since Sunday on the book thing. I have to go to Orlando tomorrow for a speech [at the NALEO conference], I have to be back in D.C. on Sunday for ‘Meet the Press,’ then I have a whole other week here. If I had gone to Utah I wouldn’t see my kids for 15 days. So I had a choice to make, and I chose my kids.”

So does this mean Rubio is choosing his kids over the vice presidency?

“No,” he said with a laugh. “I picked my kids over Utah!”

View Photo Gallery: Here’s a glimpse of the energetic Marco Rubio’s compelling — and often surprising — life story, from “The Rise of Marco Rubio,” the upcoming biography by The Post’s Manuel Roig-Franzia.

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