By Jonathan Landay, Patricia Zengerle and Yara Bayoumy
WASHINGTON (Reuters) - Under pressure from Congress, the Trump administration faces a dilemma: how to respond to the disappearance of Saudi journalist Jamal Khashoggi while ensuring that any punitive action does not alienate Riyadh, a key ally against Iran.
Leading senators have already made their displeasure clear with Saudi Arabia, with Senator Bob Corker telling Reuters, "You can’t go around killing journalists."
Saudi Arabia's denials that it had any role in Khashoggi's disappearance have fallen on deaf ears in Congress, with nearly a quarter of the Senate triggering a U.S. investigation into the case.
U.S. President Donald Trump, who forged close ties with Saudi Arabia's Crown Prince Mohammed bin Salman upon taking office, has also increasingly expressed frustration with the case.
Harsh actions against one of Trump's stalwart allies would be a sharp contrast with the administration's relatively muted tone over the kingdom's role in the war in Yemen and a crackdown on internal dissent.
Corker, the Republican chairman of the Senate Foreign Relations Committee, acknowledged the case - if Saudi responsibility is confirmed - could complicate the U.S. strategy to contain Iran, in its bid to gain influence throughout the Middle East.
"It could affect multiple things that we’re working with them on that are very important," Corker said on Wednesday, adding that the Senate's relationship with Saudi Arabia was at a "very, very low point."
Riyadh already is facing a backlash in Congress where anger has been mounting over civilian casualties in the Saudi-led coalition's campaign in Yemen.
On Wednesday, a week after Khashoggi's Oct. 2 disappearance, the White House said that senior officials had spoken to the crown prince, referred to in shorthand as MbS, and Trump described the case as a "very serious situation."
The outcry from lawmakers of both parties, including Republican allies of Trump, foreign policy analysts, former U.S. officials and leading media commentators who knew Khashoggi, has intensified pressure on the White House to take a hard line.
Khashoggi, who had been living in the United States for the past year, was last seen entering the Saudi consulate in Istanbul. Khashoggi's Turkish fiancée, Hatice Cengiz, waiting outside, said he never emerged and Turkish sources said they believe Khashoggi was killed inside the building, allegations that Riyadh dismisses as baseless.
Republican Senator Lindsey Graham, who golfed with Trump last weekend, warned on Wednesday "there will be hell to pay" if Saudi responsibility is proven.
"If they’re this brazen it shows contempt, contempt for everything we stand for, contempt for the relationship. I don’t want to prejudge, but if it goes down the road that I’m worried about it going down, contempt will be met with contempt,” he said.
Later on Wednesday, nearly a quarter of the Senate's members wrote a letter to Trump that triggered a U.S. investigation into the case that could result in sanctions against individual Saudis under a U.S. human rights law.
The Saudi embassy had no immediate comment on the letter.
Ned Price, a former Obama administration official, said he did not "foresee a strategic reorientation" in U.S.-Saudi ties unless Congress forces the administration’s hand.
"If it plays out the way it may play out, then we’ll see significant and meaningful tactical changes in the relationship that in large part are driven by the legislative branch," Price said.
Lawmakers could cut funds for Pentagon support for the Saudi-led coalition in Yemen, and press for sanctions, Price said.
The backlash could intensify if Democrats, who have led criticism of Riyadh, win one or both chambers in the Nov. 6 congressional elections.
However, they still have to be mindful of the need for Saudi cooperation on U.S. foreign policy goals, including Middle East peace, oil supplies, and missile defence system sales, analysts said.
"Riyadh is our only rational (Arab) partner because they agree with most of our long-term goals," said Hussein Ibish, with the Arab Gulf States Institute in Washington. "So the Democrats will have to keep the door open but they can still use this to seriously harm Trump on foreign policy."
But for now, the uproar is bipartisan.
"We have a common interest in limiting the spread of Iranian influence in the region, and it would impact that. But there are issues like human rights and norms of global diplomacy that always take precedence,” Republican Senator Marco Rubio told Reuters.
(Reporting by Jonathan Landay, Patricia Zengerle and Yara Bayoumy; Editing by Mary Milliken and Grant McCool)