In a Senate floor speech timed with his decision to put the nomination of Rob Portman as U.S. trade representative on hold last year, Bayh said, "It is not a sign of strength, it is not a sign of independence, it is not a sign of security when something as fundamental as the value of our money can be undermined by a slip of the tongue or a premeditated statement or a rumor sweeping a foreign capital."
"That is not the sign of a great nation," the Indiana Democrat continued, "It is the sign of dependency, of weakness."
One author who has worked to focus public attention on the perils posed by borrowed money is Kevin Phillips, the former Nixon strategist who has turned sharply critical toward the GOP since writing "The Emerging Republican Majority."
In "American Theocracy," his latest book, Phillips identifies borrowed money as one of the perils facing the United States in the 21st century -- along with oil and radical religion.
But while speaking at the AFL-CIO in April, Phillips told ABC News that absent an acute financial crisis, he doubted whether any presidential candidate could get traction in 2008 by talking about the deficit as a sovereignty issue.
"Elections turn on more visceral things than international economic issues," said Phillips.
Bayh, however, remains undaunted.
"This president talks a lot about spending and deficit, but has never vetoed a single penny of spending," said Bayh. "When I was governor, I vetoed a budget because it was unsustainable."
"Leaders make tough decisions and take tough stands," he added. "This president has been unwilling to do that."
ABC News' Dan Nechita contributed to this report.