The idea had been to use GOP control of capitals in key swing states that have gone Democratic in recent presidential races to change the rules. In 2016 and beyond, a candidate who won more votes in a state would not get all its electoral votes; instead they would be awarded by congressional district, with two votes going to the statewide winner.
The congressional map is key. Since GOP-controlled legislatures have generally redrawn districts after the 2010 census to favor Republican congressional candidates, the proposed change could allow the loser of a state's popular presidential vote to win most of its electoral votes.
But McDonnell isn't alone. Republican leaders in Florida, Michigan, Ohio, and Wisconsin - all states President Obama carried twice - have also thrown cold water on the idea. They argue that ending the winner-take-all system would reduce their states' relevance and power.
Two proposals are percolating in Harrisburg. Senate Majority Leader Dominic Pileggi (R., Delaware) plans to introduce legislation this month to split 18 electoral votes based on candidates' percentage of the popular vote statewide - with two extra electoral votes awarded to the statewide winner.
A state House proposal, brought forward by Robert Godshall (R., Montgomery) and Seth Grove (R., York), would award electoral votes by congressional district, much as Republicans have proposed in other swing states.
Lawmakers have other major issues loading their plates right now, including the budget and Gov. Corbett's proposals to privatize the state liquor system and cut public-employee pension costs.
"This is not a 'top 10' or even a 'top 20' priority," said Erik Arneson, spokesman for Pileggi. "But he does think it is an important debate to have."
Under Pileggi's formula, Obama, who carried Pennsylvania on Nov. 6 with 52 percent to Romney's 47, would have received 12 electoral votes to Romney's eight. "It's difficult to make a straightforward argument that the winner of the statewide popular vote shouldn't get the majority of the electoral votes," Arneson said.
There will probably be a hearing this spring on the proposal, Arneson said, "and then we will make a determination whether this is something worth having a vote on."
Corbett, a Republican, is "neutral" at this point, not having had time to analyze the proposal, said spokesman Kevin Harley.
The burst of interest in tweaking the Electoral College comes at a time of intense GOP soul-searching after losing the race for the White House. Republican leaders are grappling with how to better appeal to a changing electorate, with exit polls showing that Hispanic, African American, and young voters rejected the party's conservative message.
"I don't think we need to change the rules of the game," Florida House Speaker Will Weatherford, a Republican, said recently. "I think we need to get better."
Republicans who are advocating Electoral College changes say they would give smaller towns and rural areas, often overlooked in presidential races, more say in battleground states. At the same time, they would offer an advantage to the GOP, since the redistricting that followed the 2010 census tended to concentrate Democratic votes in a few congressional districts in those states - such as Pennsylvania.
Pileggi has tried before. With Corbett's support, he pushed a 2011 proposal to award electoral votes mostly by congressional district, but it went no further than a state Senate committee. Opposition was intense, centering around arguments that it would deflate Pennsylvania's power as a swing state and that it was unfair to change the rules so close to an election.
The change would have meant Mitt Romney winning 13 of Pennsylvania's electoral votes to seven for President Obama - even though Obama won the state by 309,000 votes.
The 2011 effort also ran into friendly fire. Since it would have allotted electoral votes by congressional district, some GOP incumbents in Congress warned that Democratic spending on behalf of presidential nominees might drown them, especially in suburban districts around Philadelphia.
The what-ifs abound. Since the Constitution lets each state decide how to apportion its electoral votes, what if all states used the congressional-district system? Romney would have edged Obama in electoral votes, 276-262, according to Emory University political scientist Alan Abramowitz. (Obama, who took 51 percent of the popular vote to Romney's 47 percent, won, 332-206.)
And if that system were in place just in Pennsylvania and the other swing states? Obama would have barely won, 271-267, Abramowitz calculates.
On Jan. 29, a Virginia Senate committee voted to kill legislation that would have enacted the congressional-district system. Until Obama carried the state twice, Virginia had gone Republican in every presidential vote since Democrat Lyndon B. Johnson's landslide win in 1964.
Republican Govs. Rick Snyder of Michigan, John Kasich of Ohio, and Scott Walker of Wisconsin have spurned the idea.
As for McDonnell, he is not expected to address the issue in his Harrisburg speech, GOP officials said. His subject? The future of the Republican Party.
Contact Thomas Fitzgerald at 215-854-2718 or firstname.lastname@example.org, or follow on Twitter @tomfitzgerald. Read his blog, "The Big Tent," at www.philly.com/BigTent.