In the face of mounting veto threats, subpoenas and unyielding rhetoric, tensions between Capitol Hill Democrats and the White House appear to have hit their boiling point.

But Senators and Bush administration officials acknowledged this week that despite their recent spate of very public clashes, they have not yet retreated into intractable positions and are continuing to work together privately to advance a handful of key legislative initiatives. That’s because, Democrats and Republicans said, neither President Bush nor the new Senate majority can rack up accomplishments in a vacuum.

“There’s a public relationship that goes on in front of the camera, but behind the scenes people are pretty professional,” said a knowledgeable White House official, speaking on the condition of anonymity. “There’s lots of politicking on both sides.”

Both sides are seeking to gain political advantage on scores of issues before the Senate — perhaps most notably on the pending $120 billion-plus Iraq War spending bill that has led to a virtual standoff between Bush and Hill Democrats. Bush has said he will veto the measure if it contains timelines for a troop withdrawal from the region, while Democrats have insisted that the bill require some form of deadline for redeployment of U.S. forces.

That measure is likely to be one of Bush’s first vetoes of the 110th Congress, second only to a expected stem-cell research funding measure that appears destined for the veto pen in the coming days. Bush has issued numerous veto threats so far this year, just as the Democrats have countered with oversight hearings into his policies and investigations into the controversial firings of eight U.S. attorneys.

One of the latest political power plays came while Senators were in recess last week, when Bush surprised the Democrats by installing four appointees to prominent federal posts without their confirmation. Three of those recess appointments were highly controversial among Democrats, including Sam Fox as ambassador to Belgium. As a counter, Senate Democrats are considering blocking all future Bush nominations, and shortening their August recess to make it more difficult for the White House to usurp their power.

Even so, Senators said Wednesday they don’t believe their prominent battles will yet lead to a full-scale legislative stalemate. Talks continue on numerous fronts, from immigration and health care reform to energy and trade and entitlement changes, Republicans and Democrats said.

“I haven’t given up, even on the issue of Iraq,” Majority Whip Dick Durbin (D-Ill.) said. “We need one another.”

“It’s always possible to have high-profile fights and still work behind the scenes to get things done,” added Sen. Jon Kyl (Ariz.), the GOP Conference chairman. “That’s the way Washington has worked for years.”

With Bush facing his final two years in office and Democrats in charge for the first time in practically a dozen years, both sides concede they are dependent on the other to pass laws. Bush understands he needs Democrats to help round out his legacy, while Democrats know they need the White House’s help to prove to 2008 voters that they made the right decision in 2006.

“We’re going to do our best to try to find reasonable compromise and ways to cooperate,” Durbin said.

“They’ve got to work with us, and they’ve got to work with the White House,” noted a Senate Republican leadership aide. “There’s always going to be dual-track scenarios. [Democrats] can still throw bottles over the fence to keep their base happy and still work with the White House on something.”

Even so, Senate Democrats said they don’t think Bush has yet to come to terms with the new power structure in Washington, D.C., that, in effect, forces him for the first time in his six years to deal with Democratic Congressional majorities. Bush enjoyed sizable GOP majorities for much of his tenure in Washington, with the exception of a brief 18-month period when Democrats controlled the Senate.

Sen. Barbara Boxer (D-Calif.), chairwoman of the Environment and Public Works Committee, said Senate Democrats understand that the legislative differences with the White House aren’t personal. But Boxer said Bush still hasn’t caught up with the learning curve.

“There’s no personal animosity that I can see,” she said. “I just see a basic lack of respect for our role. I took an oath of office to do my job and I take that very seriously. It’s a problem.”

“He’ll figure it out sooner or later,” added Senate Judiciary Chairman Patrick Leahy (D-Vt.).

But Kyl said it’s not that Bush doesn’t understand Congress, but rather that he feels passionately about his viewpoints and doesn’t want to cede any principled ground. Bush “doesn’t have animus” for Congressional Democrats, Kyl added, and understands all to well that his job requires him to “work under difficult circumstances with his opponents.”

“There are some things we’ve just got to work together on,” Kyl said.

Similarly, Office of Management and Budget Director Rob Portman, a one-time House Republican Member, doesn’t believe the public strife means all bets are off in terms of getting things done across the aisle this Congress.

Portman harkened back to the Clinton administration when the then Democratic president was able to work with the GOP to help usher in bipartisan welfare reform legislation and a balanced budget act.

“It is possible to put aside differences on difficult issues, compartmentalize them, and work together,” Portman said. “Maybe I am naive about this, but I don’t think these other issues have to distract us.”

Both Democrats and Republicans alike say much of the public posturing is fanned by passions on both sides on the Iraq War. And Senators across the board predicted that after the White House and Hill Democrats reach some type of agreement on the outstanding emergency spending bill that tempers will die down — at least temporarily.

“We have tensions, obviously, but they exist because we have very significant differences in policy choices,” said Sen. Byron Dorgan (D-N.D.).

But Iraq aside, Dorgan noted that Congress normally butts heads with the White House in a divided government. “That’s the way it’s supposed to work,” he said. “It’s a separation of power. That’s democracy.”

Steven T. Dennis contributed to this report.