Sen. John McCain (R-Ariz.) has yet to hint at potential contenders to head the Department of Commerce, but leading business advocates say it is likely to be someone who not only has business experience but also a close relationship with the White House.

Based on the historical pattern, “first and foremost, it is someone who has the ear of the president,” said John Castellani, president of the Business Roundtable.

Recent occupants of the office include Don Evans, a longtime friend and confidant of President Bush, as well as William Daley and the late Ron Brown, both of whom served under President Clinton and were Democratic Party insiders before becoming Commerce secretary. Barbara Franklin, who served as Commerce secretary under President George H.W. Bush, was a corporate executive and Republican insider who co-chaired Bush’s national finance committee and served as director of Republican coalitions at the party’s 1988 national convention.

Like many observers, Castellani declined to speculate on future candidates for the job, which can be even trickier to handicap than other Cabinet agencies that have a more narrowly focused portfolio.

Still, some clues have surfaced about the types of candidates McCain might tap for the post.

McCain could look to his campaign’s economic advisers, a list that includes former Hewlett-Packard President and Chief Executive Officer Carly Fiorina and former Congressional Budget Office Director Doug Holtz-Eakin. Fiorina has been one of McCain’s more visible surrogates on the campaign trail.

One business trade association executive said McCain might look to familiar and tested figures from the current administration, such as U.S. Trade Representative Susan Schwab or her predecessor, former Rep. Rob Portman (R-Ohio). Both have won high marks among Republicans and some Democrats for promoting free trade — a key objective for the Commerce Department.

In addition to trade policy, the Commerce Department runs a host of programs designed to promote U.S. business abroad. It also houses the Census Bureau, the National Oceanic and Atmospheric Administration, and the Patent and Trademark Office, all of which are important in different ways to the business community.

The executive said McCain might also look to current or former governors, who tend to have public-sector expertise promoting business themes. For “the types of people who have real life experience in creating jobs and economic development, looking at a governor makes sense,” the executive said.

The possibilities could include former Michigan Gov. John Engler (R), who now heads the National Association of Manufacturers, or former Sen. George Allen (R-Va.), who is also a former governor. If McCain wants to add a Democrat to his Cabinet, the source said, McCain could look to Sens. Tom Carper (D-Del.) or Ben Nelson (D-Neb.), who are former governors. Another possibility is Virginia Gov. Tim Kaine, who was on Obama’s vice presidential short list. (Whether any of these Democrats would join a Republican administration is another matter entirely.)

The business source said presidents don’t necessarily look for an insider, so much as someone they can trust to advance the administration’s priorities.

“We assume whoever is appointed … the president is going to pick someone who reflects his vision,” the source said.

The executive pointed to Daley and Brown, as well as Robert Mosbacher in the first Bush administration, as successful Commerce secretaries: “It’s really the president giving their Cabinet secretaries the license to push initiatives.”

Scott Lilly, a senior fellow with the liberal-leaning Center for American Progress and a former Capitol Hill aide, added that the influence of a Cabinet depends on how much leeway the White House gives the Cabinet secretaries.

“It all depends on how a president’s administration wants to use the Cabinet,” Lilly said. Under President Bush especially, “control has been so centralized in the White House. If there is a Democratic administration, one of the interesting things for observers to watch is whether that trend continues.”

Lilly said there hasn’t been much buzz about Obama’s potential picks for the Commerce post or its impact on administration policy. Lilly described the office as the modern equivalent of Postmaster General — an office that in the early part of the 20th century was often filled by a figure close to the president and/or a major player in the party, rather than a specialist in the intricacies of the department’s portfolio.

“It’s a high profile for a very significant political official, and one that you don’t have to worry about,” he said. “It’s usually been someone from the business community, often a major corporate figure.”

However, the Commerce slot isn’t always given to an insider. Bruce Josten, executive vice president for government affairs at the U.S. Chamber of Commerce, notes that current Commerce Secretary Carlos Gutierrez was CEO of the Kellogg Co. before joining the administration.

Whether the next president is McCain or Obama, Josten said the next Commerce secretary is almost certain to take a lead role in renewing expired presidential trade promotion authority and advancing trade deals.

“I don’t think it matters who is president,” Josten said. “The person who is going to be in that position is going to be an advocate for free trade.”

While McCain’s generally unabashed free-trade views differ from Obama’s more cautious approach on trade, Castellani said each candidate would face the task of adapting trade policy to rapid changes in the economy, as well as labor and environmental considerations.

“I think Sen. McCain’s and Sen. Obama’s Commerce secretary is going to face the same challenges,” Castellani said. “That difficulty is going to come from Congress.”