Are moderate Democrats losing traction in their party’s presidential primary process? A recent decision by of one of the party’s few moderate candidates seems to indicate the forever shrinking real estate moderates appear to occupy within the party of Kennedy and Roosevelt.

Tom Vilsack served two terms as the governor of Iowa, where he worked with members of both parties to reach compromise on consensus legislation. Vilsack was also the head of the Democratic Leadership Council, the centrist organization that played a huge role in the career of former Democratic standard bearers like Pres. Bill Clinton and Connecticut Sen. Joseph Lieberman. Vilsack has a good record on many issues, like taxes and energy that should, in theory, make him appealing to a national base. And he even opposes the war in Iraq and advocated an immediate withdrawal of troops from the region.

Despite all this, as well as the fact that this nation rarely elects senators to serve as its president, Vilsack consistently trailed Hillary Clinton, Barack Obama and John Edwards, all former or current senators, across the nation. Vilsack even failed to pick up a lead in his home state.

Why did Vilsack do so poorly? The candidate blames money, stating that national politics have succumbed to an invisible donor primary that gives candidates a significant edge over others even before the first ballot is cast. “I have the boldest plan to get us out of Iraq and a long-term policy for energy security to keep us out of future oil wars. Our campaign has built the strongest organization here in Iowa, with almost 3,000 supporters among Democratic caucus goers. We are organizationally positioned to win the caucuses in January 2008. We have everything to win the nomination and general election,” said Vilsack. “Everything except money.”

Other factors, besides the almighty dollar, certainly contributed to Vilsack’s failure to pick up traction across the country. The star power surrounding Clinton and Obama certainly did not help him. But a real reason a moderate like Vilsack cannot raise money might be because his traditional donors do not have a place in the Democratic primary anymore. In many ways, a more militant liberal base has become the true power behind the Democratic throne. They have flexed their power through the “netroots,” Internet communities where they push a message and throw money behind candidates to back that message up. In 2004 they made their presence known by helping Howard Dean become a serious contender in the presidential primary. They later helped Ned Lamont defeat Lieberman in last year’s Democratic primary, though Lieberman would eventually win as an independent.

They are activist Democrats, and almost totally control the Democrats’ primary process. To them, the Democratic Leadership Council, the land of Vilsack and Lieberman, is part of the problem, not the solution, when it comes to returning the Democratic Party to national glory. They seem to think stricter liberalism is what the Party needs, and that Vilsack was the victim of an unofficial litmus test at the hands of his Party’s base. He might be right on Iraq to them, especially since Congress refuses to take the binding stand on the war that Vilsack would call for. But he was part of the DLC, so there is no room for him at the liberal inn.

Obama speaks an excellent bipartisan game, but his past record is very liberal. Despite his southern roots, no one would ever confuse Edwards for a conservative. Former New Mexico Gov. Bill Richardson could be a good candidate for moderates, but he appears to be running more to become a vice-president than to actually win the nomination outright.

That leaves Hillary Clinton. She is the liberal bogeywoman of the left, but she might be the last great hope for the moderate Democrat. The “netroots” have zero sympathy for her candidacy, regarding her instead as a political opportunist who will say or do anything to get elected. But if that was the case, then she would have turned around her stance on national security and similar affairs by now. But she will not apologize for her vote on the Iraq war and no one would consider her anything but a strong supporter of Israel, two positions that have little traction on the far-left.

When Vilsack dropped out of the race, Sen. Clinton expressed her admiration for him both as a man and as a legislator. “Tom has made Iowa a leader in renewable energy and created thousands of jobs as one of America’s great governors. We share a passion for protecting America’s young people through expanded health care options, early childhood education initiatives and opening the doors to higher education to every American. I know he will continue to contribute to the dialogue about how to move America forward,” said Clinton. Whether that dialogue will have a moderate tone remains to be seen, though with Vilsack gone Clinton stands as the last best hope for middle-ground Democrats.