He decided that he stood to lose more if Terry Coleman was elected speaker of the House of Representatives without opposition than if he was elected speaker over the governor's candidate.
The question is: How did he come to that conclusion?
To win, Perdue and Rep. Larry Walker, D-Perry, needed to change the minds of 18 Democrats who voted for Coleman in November when the party caucus met to decide its speaker nominee. That would have been hard enough with a candidate who played to the governor's strengths -- say a representative popular with white, rural legislators. But Walker and the governor were ill matched for a run at speaker.
Yet Perdue persevered, and it cost him. As he readies to battle a budget deficit with tactics that may include tax hikes, and as he studies controversial proposals such as revisiting redistricting, Perdue overreached to consolidate power in a move worthy of "King Roy" Barnes. Now, the new governor's power play pits him against a speaker in control of a united House Democratic Caucus.
Perdue used precious political capital only to lose a race that elevated the power of his chief rival. At the same time, it angered the very Democrats who might have been most likely to go along with his proposals.
For most Georgians, the difference between the two speaker wannabes may seem slight, although Walker is slightly to the left of Coleman. In the so-far most-talked-about issue of the session -- ethics -- Walker had the edge. Neither Coleman nor Walker are spotless in the ethics department.
The state Ethics Commission slapped Coleman with a $6,500 fine five years ago for putting campaign money to personal use, and in 2002, he was hit another ethics complaint for the very same offense, this time for making $38,000 in condominium payments from his election account.
Walker got nailed in 2000 for sitting on a committee that decided Grady Hospital's funding while owning interests in companies that do business with the facility.
Ironically, although Walker was the more liberal of the contenders, the House under his rule would have been less able to withstand the far-right agenda of some Republicans. For example, it's less likely now that radical anti-abortion measures will pass.
To calculate the real costs to Perdue of Walker's 11th hour withdrawal from the race against Coleman, just look at the case of Rep. Mike Snow, D-Chickamauga. Snow faced a special election for his seat Jan. 7.
Walker, probably hedging his bets, called Snow to tell him he could keep the governor out of the race. But the weekend before the vote, Perdue showed up in Snow's north Georgia district with Republican Party Chairman Ralph Reed and a host of GOP dignitaries to campaign for his opponent, Jay Neal.
Walker failed to deliver and Snow, whose vote was undecided in the speaker's race until Perdue showed up, won. Snow's decision to back Coleman Monday morning became a foregone conclusion.
Snow says he's a little sore that Perdue got involved in his race. The irony, he says, is that he and the governor probably agree about more things than Perdue and Neal, who is a conservative minister.
Snow says he may still vote for parts of the governor's agenda, "but it may take me a few months. I've got to get at least a little bit even. This ain't for choirboys, you know."
Plenty of rural legislators are probably thinking the same thing after the hand-to-hand combat over the speaker's gavel, which Snow characterized as three times nastier than reapportionment. That could negatively affect Perdue's legislative agenda. After all, rural white lawmakers formed the base of Coleman's support and the target of the governor's overtures on behalf of Walker.
Trouble is, Walker wasn't nearly as popular with the same people. He was just too progressive as a legislator, argues Rep. Tyrone Brooks, D-Atlanta.
"It's ironic isn't it?" Brooks says, citing Walker's support of anti-predatory lending and hate crimes legislation. "I can't recall a single issue that I, or members of the black caucus, have had to carry that was important to the African-American community, and often times controversial, that Larry wasn't with us. He's always been there."
But in the end, a vote for Walker would have meant Republicans chairing powerful committees, and that was too much for Brooks to bear.
New House Speaker Pro Tempore DuBose Porter, D-Dublin, downplays any lingering hard feelings from the race -- but acknowledges the damage it did to Perdue.
"The governor made a tactical mistake," Porter contends. "He made Terry more powerful." Every policy issue must now also come through the House Democratic Caucus, Porter says.
University of Georgia political science professor Charles Bullock said that might just be wishful thinking.
"I don't doubt that if Terry is the new speaker that the House will be taking steps toward greater independence, but I would be surprised to see the House able or prepared to wing it on its own," Bullock says.
The fact remains that House members are part-time legislators with small staffs. The governor is the only one able to make a full-time commitment to policy development.
"A year or two years down the road, [Perdue] may not have batted a thousand, but he'll probably have a batting average that most every president would be envious of," Bullock continues.
Rep. Mark Burkhalter, R-Alpharetta, says he doesn't think Walker's defeat will shorten the governor's honeymoon with the Legislature or hamper his agenda.
That's hard to believe given just how fiercely Perdue and Walker fought for the post.
Walker contends the battle was close. He says he had 15 firm commitments Jan. 5, moved the number to 20 by mid-week but saw it dwindle over last weekend.
State Democratic Chairman Rep. Calvin Smyre says party leadership wasn't sure about the outcome until Sunday evening.