How do we know that things have gotten significantly better in Iraq?

Perhaps because of stories like this one:

As violence declines in Baghdad, the leading Democratic presidential candidates are undertaking a new and challenging balancing act on Iraq: acknowledging that success, trying to shift the focus to the lack of political progress there, and highlighting more domestic concerns like health care and the economy.

Advisers to Senators Hillary Rodham Clinton and Barack Obama say that the candidates have watched security conditions improve after the troop escalation in Iraq and concluded that it would be folly not to acknowledge those gains. At the same time, they are arguing that American casualties are still too high, that a quick withdrawal is the only way to end the war and that the so-called surge in additional troops has not paid off in political progress in Iraq.

But the changing situation suggests for the first time that the politics of the war could shift in the general election next year, particularly if the gains continue. While the Democratic candidates are continuing to assail the war — a popular position with many of the party’s primary voters — they run the risk that Republicans will use those critiques to attack the party’s nominee in the general election as defeatist and lacking faith in the American military.

If security continues to improve, President Bush could become less of a drag on his party, too, and Republicans may have an easier time zeroing in on other issues, such as how the Democrats have proposed raising taxes in difficult economic times.

“The politics of Iraq are going to change dramatically in the general election, assuming Iraq continues to show some hopefulness,” said Michael E. O’Hanlon, a senior foreign policy fellow at the Brookings Institution who is a supporter of Mrs. Clinton’s and a proponent of the military buildup. “If Iraq looks at least partly salvageable, it will be important to explain as a candidate how you would salvage it — how you would get our troops out and not lose the war. The Democrats need to be very careful with what they say and not hem themselves in.”

The usual caveats apply, of course: The situation in Iraq remains fluid and victory is not yet won. There will continue to be a need for American troops in the country and the reconstruction effort will be ongoing by the time the election rolls around.

But at the same time, it is important to note that there has been a significant and fundamental change in the narrative concerning Iraq. What was once seen as unwinnable is now palpably within reach in terms of reconstituting the country and helping to turn it into a Middle East success story. And the political dynamics here at home reflect this new reality. If things continue to go down the current positive path, it will seriously upset the conventional wisdom that has the Democrats winning the White House in 2008 thanks to public dissatisfaction with Iraq. And while Democratic candidates may strive to distance themselves from their previously resolute antiwar positions, we have the Internet to remind us of what they said, and how often they called the surge “a failure” and denigrated any and all improvements in Iraq as being ephemeral. By their judgments and predictions on this issue, we shall know them.