The furor over Saudi Arabia’s alleged role in the disappearance of Washington Post columnist Jamal Khashoggi shows the limits of the country’s efforts to win over Americans, according to one expert.

The outcry also could spur the Middle Eastern kingdom to ramp up its already-powerful lobbying and public-relations efforts in Washington, D.C., said Ben Freeman, author of “The Foreign Policy Auction” and director of the Foreign Influence Transparency Initiative at the Center for International Policy, a think tank.

“What we’ve seen in the past from a lot of countries, when it comes to their spending on lobbying and PR in D.C., is they actually tend to spend more when relationships sour in Washington,” Freeman told MarketWatch.

One example of that came last year, when Saudi Arabia and its Mideast allies had a falling out with Qatar. “After that, we really saw a lobbying blitz from both sides, with the Saudis and Emirates adding lobbying firepower in the summer of 2017, and the Qataris doing the same thing,” Freeman said.

Related:Corporate America begins to distance itself from Saudi money due to Khashoggi affair

In 2017, Saudi Arabia nearly tripled its spending on registered foreign agents to influence American policy and opinion, according to Freeman, who analyzed Foreign Agents Registration Act filings. The country spent $27.3 million, up from just under $10 million in 2016. This year’s total could be higher as Saudi Arabia has been increasing the number of lobbying firms that it works with, he added.

These totals don’t include donations to American universities and think tanks, which don’t have to disclose such contributions. Saudi Arabia’s overall 2017 spending on influencing the U.S. easily could amount to double that $27.3 million figure when such outlays are included, Freeman said.

“Arguably, in a lot of ways, they are the most influential foreign lobby in the U.S.,” the Center for International Policy expert said. China, Qatar and the United Arab Emirates could be in the same ballpark in terms of influence, he added.

Saudi Arabia’s spending on U.S. lobbying is below the outlays by South Korea, Japan and Ireland, according to data from OpenSecrets.org, which is run by a nonpartisan research group, the Center for Responsive Politics. But the Mideast nation’s outlays are particularly focused on what’s traditionally considered lobbying and public relations, Freeman said. The Saudis have paid out $23.6 million since January 2017, while No. 1 spender South Korea’s corresponding total is $72.2 million, according to the OpenSecrets.org data, which uses a different methodology than Freeman for its estimates.

“The Saudis get a lot out of their lobbying and PR expenditures,” said Freeman, noting the country’s government gets the chance to buy U.S. arms, and it also has received American military assistance in its actions in Yemen’s civil war. “From their point of view, the return on investment is just phenomenal.”

Some U.S. lawmakers have called for an end to the sales of military gear. Sen. Rand Paul, a Kentucky Republican, said in a tweet last Thursday that President Donald Trump “should immediately halt arms sales and military support to Saudi Arabia,” and Sen. Bob Corker, a Tennessee Republican and chairman of the Senate Committee Foreign Relations, said arms sales to the country were at risk. Last year, Trump signed a $110 billion arms deal with the Saudis.

At least one U.S. lobbying firm has cut ties with Saudi Arabia, joining other American companies such as J.P. Morgan Chase & Co. JPM, -0.08% and The New York Times Co. NYT, -0.26% in distancing itself from the kingdom after Khashoggi’s disappearance. The Harbour Group, a Washington firm that has advised Saudi Arabia for more than a year, ended its contract with the Saudi embassy on Thursday, according to a Wall Street Journal report.

“It is clear that many U.S. companies are feeling compelled to revisit their ties to Saudi Arabia,” said Rob Malley, president and CEO of Crisis Group and a former Obama administration adviser on Mideast policy, in an email to MarketWatch. If the reports about Khashoggi are accurate, “it is going to pull the rug from underneath the red carpet treatment the crown prince had grown accustomed to when he visits the U.S.,” Malley added, referring to Crown Prince Mohammed bin Salman, who courted Hollywood and Silicon Valley in a three-week tour this past spring.

Khashoggi, a Saudi citizen and Virginia resident known for criticizing his home country’s government, was allegedly killed this month in the country’s consulate in Istanbul, Turkey. The Saudi government has denied any involvement in his disappearance. The Turkish government claims to have audio that proves the journalist was murdered inside the consulate. Saudi Arabia is weighing whether to say that rogue operatives killed Khashoggi during an interrogation gone wrong.

On Monday, Trump said Saudi Arabia’s King Salman denied knowing what may have happened to Khashoggi, adding that he spoke to the king Monday morning. While Salman is king, he named his son Mohammed bin Salman as crown prince last year, and MBS has been tightening his grip on power. The crown prince is seen as the architect of the kingdom’s attempt to overhaul its oil-dependent economy and carve out a more muscular foreign policy.

This is an updated version of a report first published on Oct. 12, 2018.