The 2006 midterm election may be the first real test of conservative resolve since the 1994 GOP revolution as declining polls for the Bush administration and Republican candidates mean GOP backers must stick together more than ever, participants in the 33rd annual Conservative Political Action Conference said last week.

But even with political nemesis and potential Democratic presidential candidate Sen. Hillary Rodham Clinton uniting participants at the Washington, D.C., conference, many conservatives in attendance told FOXNews.com that policy differences with the White House, particularly over illegal immigration and federal spending, are major concerns siphoning off the GOP's electoral base.

Disagreements are escalating at a time when a number of vulnerable Republicans are running for re-election to Congress and several seats will be open for the taking. Political pollsters blame ongoing corruption scandals, big budget deficits and public sentiment against the war in Iraq for the seeming fatigue with the GOP.

"I think that conservatives are a bit nervous, because of the polls," said Rocco DiPippo, online columnist and editor of the The Autonomist Web log, who nonetheless questions the accuracy of such polling.

"I don't sense any panic. But there is some wariness about whether [Republicans] can clean up the negative and accentuate the positive," DiPippo added.

In a new FOX News/Opinion Dynamics poll conducted Feb. 7-8, 42 percent of those surveyed said that it would be better if Democrats gain control of Congress compared to 34 percent who prefer Republicans to remain in charge. Democrats are also favored on the issues of taxes and Iraq. President Bush's approval rating is at 44 percent, up from 41 percent in January.

"[Conservatives] are nervous about it," said David Keene, president of the American Conservative Union, which sponsors CPAC, the oldest and possibly largest annual gathering of conservatives across the country.

"I think conservatives are more concerned about the policy direction that has led to the poll numbers," Keene said, pointing to the growth of federal spending in the Republican-controlled White House and Congress over the last six years. "Poll numbers don't just happen."

Keene said he estimates that 85 percent of conservatives consider illegal immigration and border security the primary issue to be addressed, and they don't agree with the president's plan to allow illegal immigrants living in the United States to stay in the country with temporary work visas.

"There is a concern and you know what the number one issue is? Border security," said Chris Simcox, president of the Minuteman Civil Defense Corps, a group of volunteers that has been monitoring the U.S. borders for illegal immigrants and reporting them to the U.S. Border Patrol.

"It is important for the Republican Party to realize that … we have a public safety issue here," said Simcox, who warned that conservatives could turn to third party candidates who make opposition to illegal immigration a cornerstone of their campaigns.

"I think there is apprehension when we get away from our conservative message," said Jessica Echard, executive director of the conservative Eagle Forum. "The White House is not good on the immigration issue. That's the clearest example."

Conservative commentator George Will told a packed CPAC audience last Thursday that he is disappointed with the Republican Congress and the White House on a number of fronts, from passage of campaign finance reform and big spending deficits to the war in Iraq and the National Security Agency wiretap controversy.

Will said the president's assertion that he had inherent constitutional authority to pursue using warrantless wiretaps on calls between people abroad with suspected links to Al Qaeda and individuals in the United States is "a stretch …that conservatives should not docilely accept."

Talk of the party's shortfalls, not to mention criticism of the White House, had been virtually unheard of in past CPAC events, particularly last year, after big presidential and congressional victories.

Like then, conservatives defended Bush against what they say is media bias against the president and GOP. But conservatives had little trouble this year discussing the public criticism over the administration's response to Hurricane Katrina, lobbying scandals tied to Republicans and the political troubles of Rep. Tom DeLay, R-Texas, who was forced to resign his post as House majority leader after being charged with conspiracy and money laundering in his own state.

"There is a necessary apprehension among several Republican leaders that I've talked to," said Phil Kent, president of the American Research Foundation, a conservative immigration policy group.

"The effect of the media focus on the scandals could take a toll in some target races," Kent said.

"If the focus is the so-called 'culture of corruption' in the Republican Party, the bitter aftermath of Hurricane Katrina and domestic issues … the Republicans will probably lose seats," added Michael Lopez-Calderon, a CPAC participant from Maryland.

On the other hand, Calderon said if conservatives use an emerging, positive strategy to defeat the Democrats in 2006 by relying on longtime GOP strengths like the War on Terror and national security, "then we will actually gain seats."

"Most Americans are not sophisticated constitutional scholars," he said, referring to the Democrats' argument against the NSA wiretap program, "but they are sophisticated about protecting their children."

According to the February FOX News poll, Republicans are still favored on family values and handling terrorism, though Democrats are narrowing the gap.

Most conservatives who talked to FOXNews.com said while Republicans are more vulnerable this year than in the previous decade, Democrats are still not offering a valid alternative and may be blowing their chance to seize the momentum.

"I think the Democrats are finished," said DiPippo.

"I don't think the Democrats are coherently behind anything. They are more about what they are against," said Michael J. Sandoval, who sold conservative-themed bumper stickers, coffee mugs and t-shirts in the conference's main exhibition hall. "I think (Sen. John) Kerry lost in 2004 because he expressed that."

Keene added: "The general public's sense is that if Republicans are the problem, Democrats aren't the answer."

Chris Green, who runs FreedomGear.com, said the confirmation of two of President Bush's Supreme Court nominees has boosted morale and united the base in recent months. "I really think the big factor is going to be the Supreme Court nominations," and, "of course, the economy will make a big difference in 2006."

Richard Mason, who assisted the "Americans for Dr. Rice" booth, dedicated to drafting Secretary of State Condoleezza Rice for a 2008 presidential run, said he only saw positive developments boosting Republicans in this year's elections.

"I've been very skeptical of the polls," he said. "[Conservatives] do see that the economy is doing so well and asking, 'Why we aren’t getting the credit.' There is progress being made in Iraq. There have been no terrorist attacks. I wouldn't say we are worried about the mood of the country."