Jim McTague of Barron’s devotes his latest “D.C. Current” column to the curious actions of the Business Roundtable, a group which surprised observers this month by endorsing President Obama’s ideas for addressing the federal fiscal cliff.

This is a delicious tale of intrigue and double crosses that demonstrates how Obama has outwitted the Republican leadership. As Boehner and McConnell have been parrying his skilled thrusts, their supposed allies at the Business Roundtable have critically wounded them from behind. The motive: self-interest. Obama offered to lower corporate-tax rates if the BRT supported his plan for personal income-tax hikes on the wealthy. This development demonstrates the wisdom of the classic quip: If you want a friend in Washington, D.C., get a dog. …

… The GOP’s negotiating position has been fairly consistent: The president must suggest detailed, meaningful reductions in the rate of government spending before Republicans will accept his call for higher tax revenue. The GOP prefers to raise revenue by limiting tax loopholes; Obama would prefer to crank up rates, but the Republicans have signaled that they might accept a hybrid approach. Higher rates, the GOP asserts, would slow the economy. The Business Roundtable was a rock-solid endorser of this view until Dec. 5, when it invited the president to address about 100 of its members to make his case for increasing Uncle Sam’s paycheck take. The press was booted from the assembly hall when it came time for the CEOs to ask questions of the president. Apparently, he said something they liked. The following week, they endorsed his call for higher personal income taxes on those making $250,000 or more a year.

The Business Roundtable, I deduce, had made up its mind before Obama stepped onto its stage. The very act of inviting him to give a televised speech without public rebuttal symbolically told the world that the organization had jumped ship.

REPUBLICANS SEETHED — in silence. Neither Boehner nor McConnell want to publicly admit what is so obvious — they’ve been left bleeding by the business group’s abrupt defection. As a man paid to be somewhat cynical, I also surmise that the Republicans remain mum because Big Money controls politics. Rare is the bird who can run for office without corporate sponsorship.