At the beginning of what is shaping up as America’s summer of discontent, U.S. Sen. Russ Feingold appeared on NBC’s “Meet the Press” for a discussion about his opposition to the war in Iraq and the prospect that he might seek the presidency in 2008 as the candidate of Democrats who want their party to propose a dramatic departure from Bush administration foreign and domestic policies.

The program’s host, Tim Russert, asked Feingold: “When will you decide whether you’re running?”

“I’m going to look at this, Tim, after the elections in 2006,” replied the maverick senator from Wisconsin. “I need to look at what happens in the congressional races — how are the ideas I’ve been presenting resonating with the American people — and decide whether this is something that makes sense or whether it’s better for me to remain in the United States Senate.”

On August 8, months before the point in November when all the 2006 results will be known, Feingold has gotten a strong and positive signal about how the ideas he’s been presenting are resonating.

Anti-war challenger Ned Lamont’s Connecticut Democratic primary win over pro-war incumbent U.S. Sen. Joe Lieberman Tuesday was a clear victory for the activist wing of the Democratic Party that — if liberal Internet blogs are to be believed — sees Feingold as perhaps its most attractive contender for the party’s presidential nomination in 2008.

On the morning after the Connecticut results came in, Feingold notes, a former staffer told him, “Hey, if you were looking for an excuse to not run for president, Russ, you didn’t get it last night.”

Feingold, whose Progressive Patriots Fund political action committee dispatched a check for $5000 to the Lamont campaign on Wednesday, describes the primary win by the anti-war challenger as “an affirmation of something much larger than Joe Lieberman or Ned Lamont.”

The message to Democratic leaders who are still uncertain about whether to aggressively oppose the war, said Feingold, was beyond debate: “You are simply not listening if you don’t know that the American people have had it with this mistake and want it to end.”

Feingold’s not just jumping on the Lamont bandwagon.

The Wisconsin Democrat was the first member of the party’s Senate caucus to speak favorably about the primary challenge by anti-war businessman Lamont to Lieberman, the Connecticut Democrat who has been the party’s most high-profile supporter of the war in Iraq and the Bush administration foreign policies that Feingold has so vehemently opposed.

Back in June, when he spoke to Russert, Feingold pointedly refused to endorse Lieberman for re-election, splitting with most other Senate Democrats and most of the party’s Washington establishment. While he did not endorse officially endorse the challenger, the Wisconsin senator said, “I think Ned Lamont’s positions on the issues are much closer to mine on the critical issues.”

Now that Lamont has defeated Lieberman, Feingold has an indication that his ideas are resonating with Democratic voters — and candidates.

In fact, Lamont cites Feingold as an inspiration and says he would side with the senator on many matters, including a controversial move to censure President Bush for authorizing the controversial warrantless wiretapping program from which most Democratic senators have distanced themselves.

For his part, Feingold says that Lieberman’s “extreme support of this … obviously mistaken (Iraq war) policy that has hurt so many Americans has put him in political jeopardy.”

The Wisconsinite also argues that the Lamont victory sends a signal that Democrats can oppose the war and still be seen as friends and supporters of the troops, a theme Lamont echoed in his victory speech Tuesday night when he said: “We have 132,000 of our bravest troops stuck in a bloody civil war in Iraq and I say its time to bring them home to a hero’s welcome.”

It is not difficult to imagine Feingold borrowing that line from Lamont as he heads out on the presidential campaign trail, just as the Connecticut candidate borrowed themes from the Wisconsin senator. The Connecticut results are only a piece of the puzzle for Feingold, who has taken steps to build the organization needed to mount a presidential run and has traveled frequently to Iowa, New Hampshire and other early caucus and primary states in recent months.

But it’s a significant piece. Lamont’s win appears to indicate that the Wisconsin senator’s unapologetic progressive positions — a “Bring the Troops Home” stance on the war, strong support for civil liberties at home, opposition to Bush administration trade and economic policies — have far more appeal among grass-roots Democrats than they do with the party’s Washington elites.

Feingold has long complained that congressional Democrats who fail to support calls for the withdrawal of U.S. troops from Iraq are out of touch not just with their own party but with the country.

“Those who vote against bringing the troops home don’t get it. They’re not out there enough. They’re not listening to the people. Frankly, they’re not even looking at the polls,” says the senator.

“I have been all over Wisconsin, all 72 counties, to 12 different states. I can tell you, the one thing I’m sure of [is that] the American people have had it with this intervention. They do want a timetable for bringing home the troops.”

That message would likely be at the heart of a Feingold presidential campaign, along with the senator’s suggestion that Democrats need to be bolder in their opposition to Republican policies.

“We lost in 2000, we lost in 2002, we lost in 2004,” says Feingold. “Why don’t we try something different, like listening to the American people?”

Connecticut voters echoed that theme on Tuesday. But in so doing, they may have complicated things for Feingold. The one thing that could trip up the Wisconsin senator’s leap onto the national stage could be the fact that a number of other Democratic presidential prospects also seem to be getting the message from Connecticut.

Massachusetts U.S. Sen. John Kerry, who frustrated many Democrats with his tepid stance on the war as the party’s 2004 presidential nominee, this year co-sponsored Feingold’s call for a withdrawal timeline. Though Kerry and Feingold are working together on the Senate floor, there is a strong sense among political observers that the Massachusetts senator is trying to occupy the political high ground that Feingold previously had pretty much had to himself.

Former North Carolina U.S. Sen. John Edwards, the party’s 2004 vice presidential nominee and an all-but-announced 2008 contender, has publicly apologized for voting in 2002 to authorize Bush to attack Iraq. Edwards as well, has been taking Feingold-like stands on a host of issues. This coming week, he will campaign in Connecticut with Lamont.

Even New York Sen. Hillary Rodham Clinton, the presumed Democratic front-runner in 2008, has begun to back off her pro-war position, which until recently was only slightly less strident than Lieberman’s.

Clinton did not vote for the June Senate resolution that Feingold and Kerry proposed to establish a withdrawal timeline, but she did back a milder resolution sponsored by Michigan Democrat Carl Levin and Rhode Island Democrat Jack Reed that prodded the Bush administration to begin taking steps to draw down the troop presence in Iraq.

Last week, as the Connecticut primary approached, Clinton engaged in uncharacteristically aggressive questioning of Secretary of Defense Donald Rumsfeld during a Senate hearing.

Though she and most other top Democrats backed Lieberman in the primary, Clinton distanced herself from the incumbent in July after he announced that if he lost the Democratic nomination he would campaign in November as an independent.

Clinton said she would back the winner of the primary, in a move that effectively shut down talk that Washington Democrats might stick with Lieberman even if he was rejected by the Democratic voters of Connecticut. On the Wednesday after the primary, she made good on her pledge by warmly endorsing Lamont, as did most other Democratic party leaders.

Like many of her other recent moves, Clinton’s declaration of party loyalty was an indication that she and other Washington Democrats are increasingly aware — and perhaps even respectful — of the anti-war ferment at the party’s grassroots. With an anti-war Democratic primary challenger of her own, labor activist Jonathan Tasini, Clinton does not want to end up in Lieberman’s position. Nor does she want to cede too much political ground to Feingold.

After all, while Clinton is the clear leader in most early polls, a New Republic cover of some months ago pictured the New York senator as a sword-swinging Goliath. Feingold was also pictured … as slingshot-wielding David.

Now that Connecticut Democrats have rejected a Democratic senator who backed the war in much the same language that Clinton has, the anti-war David of the Democratic Party is surely standing a little taller — and feeling a little more confident as he considers a presidential run.