Transportation Secretary Norm Mineta is no party animal.

The one-time California Congressman, who is now the lone Democrat in President Bush’s Cabinet, has been perhaps the most “invited” man of the political convention season. But he’s strictly regrets only, says a Mineta spokesman.

“For us, there was never a question” about whether the secretary would attend the conventions, Transportation Department spokesman Robert Johnson said last week.

When he took the job at Transportation, Mineta made clear he would not serve any political role for the president or the Republican Party, Johnson noted.

So what does the Cabinet’s only political free agent do while the GOP establishment congregates in New York City this week?

“He’ll be doing secretarial things,” Johnson said. “He didn’t go to the [Democratic National Convention], and he won’t go to the” Republican National Convention.

Johnson added, “This is the way he has conducted himself since he took the job.”

To some, Mineta’s role inside the Bush administration has appeared to be somewhat ambiguous during the last four years, in large part due to his obligation to tout the president’s transportation policies and record.

Mineta’s office also is, by tradition, functionally different from other key cabinet posts. Unlike the secretaries of Defense, Homeland Security, State and Treasury, the transportation secretary is not obligated to avoid activities that can be construed as partisan.

Even for the above-the-fray secretaries, however, some leeway exists. For instance, Treasury Secretary John Snow’s travels this year have shown a particular fondness for battleground states.

This may or may not be by design. But Snow has appeared regularly in these visits with other officials from the Bush administration’s economic team — including Labor Secretary Elaine Chao and Steven Friedman, the president’s chief economic adviser — who are promoting the president’s economic policies and plans.

Snow already has visited Florida and Ohio four times this year. The remainder of his public schedule is packed with trips to Arizona, Arkansas, Iowa, Maine, Missouri, New Hampshire, New Mexico, Nevada, Oregon, Pennsylvania, Washington and West Virginia — all presidential battlegrounds.

Indeed, the morning after President Bush delivers his Thursday speech to convention delegates, Snow will head up to Philadelphia to meet with local business leaders.

Asked last week whether Snow will use the occasion to tout the agenda laid out by President Bush the previous evening, Treasury spokesman Robert Nichols replied, “Obviously, I suspect he’ll be asked about it.”

Nichols said the secretary will be “literally everywhere” in the two months remaining before the Nov. 2 election, “talk[ing] about the president’s economic policies.” Even as Nichols was being interviewed, his boss was preparing to embark on another journey — to Grand Rapids, Mich.