As Barack Obama begins his second term today, it’s worth pondering what history tells us about his prospects for success as a two-term president. Let’s look first at the history and then at the Obama presidency in the context of that history.

Of the country’s forty-four presidents, just twenty-one—fewer than half—have served two terms or partial terms. In this category are those who have been elected twice or been elected in their own right after inheriting the presidency in the middle of their predecessors’ terms (Truman, for example, or Coolidge). Thus, it’s fair to say that a certain distinction attaches to those presidents who have persuaded the voters that they deserved a second term based on first-term performance.

And that distinction clearly attaches to Barack Obama. Thus, he’s in a favored circle, but not yet in the most distinguished circle. That distinction belongs to two-term presidents succeeded by presidents of their own party. This denotes that not only were their first terms successful in the eyes of voters but that their second terms also were sufficiently successful that the voters felt no need to abandon the incumbent party. Obama, of course, hasn’t yet had a chance to demonstrate his eligibility for this honored category, but the outcome ultimately will help determine his place in history.

We have had twelve presidents who served two terms or partial terms and then retained party incumbency. They are George Washington, Thomas Jefferson, James Madison, James Monroe, Abraham Lincoln, Ulysses Grant, William McKinley, Theodore Roosevelt, Calvin Coolidge, Franklin Roosevelt and Ronald Reagan. We can say that these men presided over relatively good times (Monroe, McKinley, TR, Coolidge) or got the country through bad times in ways that generated confidence and support across a broad spectrum of the electorate (Lincoln, FDR, Reagan).

What can we say about the two-term presidents who weren’t succeeded by their own party? Looking at their records, we see a relatively or substantially successful first term (hence reelected) followed by a seriously or moderately less successful second term (hence, White House turnover). Often a close analysis of the first term reveals weaknesses or flaws that didn’t catch up with them when they faced the voters for reelection but then overwhelmed them during their second terms.

George W. Bush is a good example. He took the country into an ill-conceived war in Iraq, but the true folly of that adventure wasn’t clearly discernible to the American people when Bush faced reelection in 2004. Soon after his reelection, however, it became clear to most Americans that the president had led the country into a quagmire that was going to yield few substantive national benefits. Similarly, his early economic policies (including, in my view, his tax cuts) yielded a strong economy in the last three years of his first term, including an election-year GDP growth rate of 3.47 percent. But soon into his second term it became clear that his fiscal indolence was crushing prospects for ongoing growth and putting the economy at risk.

All this caught up with him in his second term, leading to a devastating blow to his party in the 2006 midterm elections and destroying any chance that his party could keep the White House after his departure.

Looking at Obama’s first term, do we see a flaw likely to catch up with him in the second term? It may be that his brilliance at political tactics and partisan maneuver has shrouded from his consciousness the country’s more strategic challenges—most crucially, the monstrous debt overhang bearing down on the nation, currently at sixteen trillion dollars and rising.

This debt now represents more than 70 percent of the country’s GDP. Most experts believe that when it hits 90 percent it will begin to have a seriously deleterious impact on the economy. Every year that that percentage number rises is a year closer to an economic crisis with very high prospects of spinning out of the control of policymakers.

What did Obama do about this in his first term? Nothing good. He added nearly $6 trillion to the national debt by running massive deficits year after year. Then he promised the American people that if the most wealthy Americans would just "pay a little more," the country’s fiscal woes could be seriously ameliorated. Not true.

In fact, the country’s most ominous fiscal problem is out-of-control entitlement spending. But it isn’t clear the president intends to address this problem, and powerful forces within his party are adamantly opposed to any such initiatives.

In an interesting piece in Politico the other day, Jonathan Martin and Maggie Haberman suggest the Democrats face an underlying split between center-left elements who advocate an approach akin to Bill Clinton’s presidential stewardship and "a populist, left-leaning approach that mirrors their electoral coalition." The reporters add that the issue to watch in determining which direction the party chooses will be "the entitlement debate."

True enough. And the answer to this question also will signal just how serious Democrats are about the powerful debt overhang threatening the country’s financial health. Not coincidentally, it also will tell us how serious Obama himself is about this problem. After all, while taxes clearly will have to be part of any solution to the fiscal threat, the biggest contributor to the country’s financial threat is federal entitlement spending.

But any effort to address that matter—to raise the eligibility age for Medicare, for example—raises hackles with many liberal Democrats. Martin and Haberman quote Ohio’s Democratic Senator Sherrod Brown, for example, as saying such an approach would be "morally reprehensible."

The Martin-Haberman article explores the underlying split within the party over such issues and speculates on how Obama will seek to maintain party harmony and cohesion in the face of ongoing party divisions. But the big question facing Obama now is not intraparty leadership or even his success or failure in outmaneuvering opposition Republicans, an activity at which he has demonstrated considerable skill.

The big question is performance on such matters as economic growth, jobs, economic stability, soundness in foreign policy, lack of scandal, domestic tranquility, policy innovation and the like. These are the kinds of issues that determine a president’s standing with voters—and in history. He may pull his party together, but if he does so with policy prescriptions that generate problems for the nation, as George W. Bush did in his second term, then his party will be dealt a blow from the electorate at the next election, and his historical reputation will suffer.

And it isn’t likely that Obama’s standing with either voters or historians will be very buoyant if he either refuses or fails to deal effectively with the debt overhang and thus allows the debt to approach that ominous 90 percent of GDP, where it is headed under current policies. Presidents are elected to solve the nation’s most pressing problems—even those that aren’t readily visible on the surface of things; even those that generate strong undercurrents of controversy. And the debt overhang represents the country’s most serious economic threat.

Thus, if Obama wants a second term that places him in the most distinguished circle of presidents—two terms followed by party retention—he will fashion a brand of politics that enables him to deal successfully with the debt overhang.

Robert W. Merry is editor of The National Interest and the author of books on American history and foreign policy. His most recent book is Where They Stand: The American Presidents in the Eyes of Voters and Historians.