To the surprise of almost no one, Barack Obamaa picked Delaware Senator Joe Biden for his running mate.

Last summer, I linked to a Christian Science Monitor piece about Biden and his faith. (The article is perhaps the definitive glimpse into Biden’s Catholic values and upbringing, and bears reading. The original is right here.) The profile quoted a book Biden had written called “Promises to Keep“:

“My idea of self, of family, of community, of the wider world comes straight from my religion. It’s not so much the Bible, the beatitudes, the Ten Commandments, the sacraments, or the prayers I learned. It’s the culture,” he writes.

That comfort zone extended to the Biden family. “At the time that I was going to Catholic school and living in my parents’ home, there was a perfect fit between the theology of the church and the philosophy of my parents,” he told the Monitor.

In the Biden family, children were taught to respect the habit, but not necessarily the person in it. As a boy, Biden took endless ribbing from classmates for a stutter he later overcame. Much of the time, the nuns tried to help. But when a seventh-grade teacher mimicked Bu-bu-bu-bu-bu-Biden’s stutter in front of the class, his mother, Jean, demanded a meeting with the principal and the offending nun. “If you ever speak to my son like that again, I’ll come back and rip that bonnet off your head,” she said. Later, when then-Senator Biden told her he was going to visit the pope, she said: “Don’t you kiss his ring.”

In junior high school, Biden considered, briefly, entering a seminary in Baltimore to become a priest. His mother had other ideas. “I told him: ‘Wait until you start dating girls, then go,’ ” said Mrs. Biden, in a brief conversation after a speech her son gave at the National Press Club Aug. 1. Biden later confirmed the incident. “I can’t believe she told you that,” he says. “My mother thought I had to experience life first, and she was right.”

Biden was one of the first Catholic politicians of the Vatican II generation. From 1962 to 1965, the Vatican Council II produced documents that opened the door to ecumenical dialogue, freedom of religion and conscience, and greater involvement of the laity in affairs of the church, including saying the mass in English and more emphasis on individual Bible study.

“I was raised at a time when the Catholic Church was fertile with new ideas and open discussion about some of the basic social teaching of the Catholic Church,” Biden says. “Questioning was not criticized; it was encouraged.”

He recalls a question in a ninth-grade theology class at Archmere. “How many of you questioned the doctrine of transubstantiation?” the teacher asked, referring to the teaching that the bread and wine change into the body and blood of Christ during the Eucharist. No hands were raised. Finally, Biden raised his. “Well, we have one bright man, at least,” the teacher said.

The teacher didn’t say criticizing the church was good. “He led me to see that if you cannot defend your faith to reason, then you have a problem,” Biden says.

Meanwhile, here’s how the New York Times reports it this morning:

Senator Barack Obama has chosen Senator Joseph R. Biden Jr. of Delaware to be his running mate, turning to a leading authority on foreign policy and a longtime Washington hand to fill out the Democratic ticket, Mr. Obama announced in text and e-mail messages early Saturday.

Mr. Obama’s selection ended a two-month search that was conducted almost entirely in secret. It reflected a critical strategic choice by Mr. Obama: To go with a running mate who could reassure voters about gaps in his résumé, rather than to pick someone who could deliver a state or reinforce Mr. Obama’s message of change.

Mr. Biden is the chairman of the Senate Foreign Relations Committee, and is familiar with foreign leaders and diplomats around the world. Although he initially voted to authorize the war in Iraq — Mr. Obama opposed it from the start — Mr. Biden became a persistent critic of President George W. Bush’s policies in Iraq.

The brief text message from the Obama campaign came about 3 a.m., less than three hours after word of the decision had begun leaking out. “Barack has chosen Senator Joe Biden to be our VP nominee. Watch the first Obama-Biden rally live at 3pm ET on www.BarackObama.com. Spread the word!”

His e-mail announcement began: “Friend — I have some important news that I want to make official. I’ve chosen Joe Biden to be my running mate.”

The selection was disclosed as Mr. Obama moves into a critical part of his campaign, preparing for the party’s four-day convention in Denver starting on Monday. Mr. Obama’s aides viewed the introduction of his vice presidential choice — including an afternoon rally Saturday at the old State Capitol in Springfield, Ill., the same place where Mr. Obama announced his candidacy on a freezing winter morning almost two years ago — and a tour of swing states as the beginning of a week-long stretch in which Mr. Obama hopes to dominate the stage and position himself for the fall campaign.

Word of Mr. Obama’s decision leaked out hours before his campaign had been scheduled to inform supporters via text and e-mail message, and hours after informing two other top contenders for the vice presidential nomination — Senator Evan Bayh of Indiana and Gov. Tim Kaine of Virginia — that they had not been chosen.

As the selection process moved to an end, Senator Hillary Rodham Clinton of New York, whom Mr. Obama had defeated in his bid for the Democratic presidential nomination, had slipped out of contention — to the degree that Mr. Obama had never seriously considered her.

Mr. Biden is Roman Catholic, giving him appeal to that important voting bloc, though he favors abortion rights. He was born in a working-class family in Scranton, Pa., a swing state where he remains well-known. Mr. Biden is up for re-election to the Senate this year and he would presumably run simultaneously for both seats.

Mr. Biden is known for being both talkative and prone to making the kind of statements that get him in trouble. In 2007, when he was competing for Mr. Obama for the presidential nomination, he declared that Mr. Obama was “not yet ready” for the presidency.

The McCain campaign jumped on that early Saturday, as it responded to the selection, offering a glimpse into the line of criticism that awaits the Democratic ticket.

“There has been no harsher critic of Barack Obama’s lack of experience than Joe Biden. Biden has denounced Barack Obama’s poor foreign policy judgment and has strongly argued in his own words what Americans are quickly realizing — that Barack Obama is not ready to be President,” said Ben Porritt, a spokesman for Mr. McCain.

Meantime, there’s also a very interesting “religious biography” of Biden put out by the Pew Forum.