Members of the Republican money machine that powered presidential elections from their time as “Rangers” for George W. Bush are betting almost entirely on Mitt Romney, but a large majority has so far sat out of the 2012 race altogether.

The role of these donors has only been heightened as loosened campaign-finance laws mean some “bundlers” who affected previous races by gathering contributions from equally wealthy colleagues have instead given massive amounts directly.

This year, 620 bundlers for Mr. Bush and Sen. John McCain tracked by The Washington Times have given more than $12 million of their own funds in federal elections, with more than $1.5 million going to Romney vessels, vastly more than for any other presidential candidate.

The elites’ second-favorite candidate, former Minnesota Gov. Tim Pawlenty, has dropped out of the race, and the only other contender to receive significant backing was Texas Gov. Rick Perry.

The party committees, chiefly the Republican National Committee, raised considerably more than $4 million from bundlers and family members, who can give up to $30,800 each. Yet three donations from bundlers to a super-PAC set up by former Bush aide Karl Rove, American Crossroads, nearly matched that amount, illustrating the extent to which super-PACs are poised to usurp traditional responsibilities of the party...