Sen. Evan Bayh, weighing a run for president in 2008, challenged the Democratic Party to establish an agenda aimed at middle-class voters, a critical constituency that he said the party has let slip away.

"We may consider ourselves the party of the middle class, but too many middle-class Americans no longer consider us their party," the Indiana Democrat said Monday. "They have left the Democratic Party in droves — costing us the last two presidential elections and the last six congressional elections. If we don’t learn some lessons, we’ll lose in 2006 and 2008 as well, and we must not let that happen."

In his speech, Bayh said the party has focused most of its attention on the needs of lower-income Americans, but it also must address issues that matter to people on the next rung up the economic ladder.

"Without an agenda that speaks directly to the middle class and all who aspire to it, we will no longer be the party of Roosevelt, Truman, Kennedy and Clinton. And we will not be a majority party," Bayh said, invoking the names of former Democratic presidents.

Moreover, Bayh said: "The country’s not going to fulfill it’s potential."

The two-term senator and former Indiana governor delivered what his advisers called a "major address" in Washington and then in Iowa, the first caucus state in the presidential primary process.

Bayh has been a frequent visitor to Iowa as he decides whether to seek the Democratic presidential nomination in what already is considered a crowded field. A recent state poll showed him trailing far behind other potential Democratic contenders.

Bayh dismissed the results, saying polls change over time, and acknowledged that he’s considering running for president. He said that should he decide to run, creating opportunities for the middle class will be a focus of his campaign.

"I’m going to make it the centerpiece, not the afterthought," Bayh said as he laid out proposals for making college more affordable, curtailing rising health care costs, strengthening retirement accounts and conserving energy — a full 18 months before the Iowa caucuses.

Associated Press Writer Erica Werner contributed to this report.

© 2006 The Associated Press