WASHINGTON (Reuters) - In the Trump White House, it’s getting lonely at the top. President Donald Trump’s fellow Republicans in Congress are showing signs of going their own way, both on politics and policy, determined to salvage what they can of their agenda on healthcare and tax reform in the wake of one of the most difficult weeks of any American presidency. At the same time, Trump’s failure to fill senior roles at federal agencies means he does not have a cadre of loyalists who can help rein in a bureaucracy that many in Trump’s orbit believe are out to leak information intended to damage the president. That has worsened the isolation of the White House in a city that relies on friends and allies to shake off a crisis. The result is problems on multiple fronts: a government whose bonds with Congress, federal agencies and the public look increasingly fractured; an ambitious but stalled program of reforms; and a president whose low approval ratings threaten his party’s control of Congress in the 2018 midterm elections. Trump and his beleaguered staff, some White House aides told Reuters, feel besieged by a parade of negative stories and abandoned by fellow Republicans on Capitol Hill, as the furor over the firing of FBI Director James Comey and allegations that Trump tried to influence the probe into Russian meddling in last year’s election show little sign of abating. Since Tuesday, when leaked excerpts of a purported memo by Comey detailing his conversations with Trump were made public, few Republicans beyond the White House have rushed to the airwaves to push back against suggestions that the president may have obstructed justice in asking Comey to end the probe into the conduct of former National Security Adviser Michael Flynn. As the Russia probe entered a new phase on Wednesday with the appointment of former FBI Director Robert Mueller as special counsel in the investigation, a move that will likely place the White House under even stronger scrutiny, some Republicans expressed surprise that the White House had not done more to recruit them to backstop the president. “It’s kind of funny. The answer is no,” said Senator James Inhofe, a Republican from Oklahoma, when asked by Reuters whether the White House had reached out to him to come to Trump’s defense. “I don’t know anyone else that has been contacted.”     The White House did not respond to a request for comment on this story. Trump left on Friday for his first foreign trip as president. The 10-day trip will take him to Saudi Arabia, Israel, and Europe.     The administration has continued to struggle to fill the hundreds of open positions at senior levels of government that remain open, leaving the White House alone to grapple with one challenge after another. For example, the Justice Department still lacks senior officials in place to head up the anti-trust, civil rights, criminal, and civil divisions, as well as the Bureau of Alcohol, Tobacco, Firearms and Explosives, according to its website. At the Department of Homeland Security, the chiefs of the U.S. Customs and Border Protection, Immigration and Customs Enforcement, and the Transportation Security Administration, have yet to be confirmed. And at the Department of Education, a sprawling bureaucracy of 4,400 employees with a $68 billion budget, “all the key roles except for the secretary remain empty or filled with people in an acting capacity,” said a Department of Education official. “Nobody knows when or if they will be filled anytime soon,” said the official, who declined to be identified by name. The department did not respond to a request for comment. Trump has frequently complained that Senate Democrats have stalled the approval process for his nominees. But the White House has also been slower to send nominees to the Senate than previous administrations. Many top State Department posts also remain vacant. One consequence, say several officials, is that department experts played little role in briefing Trump for his telephone call to Russian President Vladimir Putin or his meeting with Russian Foreign Minister Sergei Lavrov and Ambassador Sergei Kislyak, where officials say he disclosed highly classified intelligence. State Department and intelligence officials say that as power is increasingly concentrated in the hands of a few Trump loyalists in the White House, the roles of professional Foreign Service, intelligence and civil service officers have shrunk compared to past administrations. For instance, said two U.S. diplomats, no one from the State Department attended Trump’s Feb. 15 meeting with Israeli Prime Minister Benjamin Netanyahu - a sharp contrast from past administrations which would typically staff such a high-profile meeting with high-level State Department officials. Asked for comment, the State Department would not address the circumstances of the meeting with the Russian officials in the Oval Office, but did speak to the efforts involving Netanyahu and the Middle East.  “As the president has repeatedly noted, Middle East peace is a top priority for this administration,” a department spokesperson said. “This is an effort supported by both the White House and the State Department. Claims that the State Department has not been involved have no basis in facts.”  Overall, more than 500 of the 557 federal government positions requiring Senate confirmation remain vacant. Only 33 nominees have been confirmed, and only 57 other positions now have a nominee, according to the Partnership for Public Service, a nonprofit, nonpartisan organization in Washington.     A lack of communication from the White House left many Republicans on Capitol Hill frustrated as a sense of crisis mushroomed over the past week. One, Richard Burr, chairman of the Senate Intelligence Committee, which is conducting its own Russia probe, publicly complained about the situation. Tuesday morning, after news broke the previous evening that Trump had shared classified information with Russian officials, Burr said he couldn’t get through to the White House, as the story lit up television news programs and buzzed online.  “Maybe they’re busy,” he said. Some Republicans said the constant focus on responding to allegations concerning the Russia probe was draining their caucus of focus and energy to push through their agenda. Absent guidance, Republican staff members in Congress were beginning to devise their own strategy about how to respond to the gusher of bad news, one aide told Reuters.  And at the White House, with lines of communication to Congress seemingly frayed at times, a narrowing circle of people has come to the president’s defense, as senior staff grapple not only with the cascade of revelations but with a president who at times contradicts on Twitter their talking points. “Everyone is just tired,” said one White House aide. 