Facebook European headquarters in Dublin. (Aidan Crawley/Bloomberg)

President Trump has singled out Ireland for its extraordinarily low corporate tax rate, making the case that the United States must overhaul its own tax code to win back American investment and jobs.

"For too long, our tax code has incentivized companies to leave our country in search of lower taxes," Trump said late last month. "Many, many companies, they're going to Ireland. They're going all over."

But Irish government officials, accountants and highly skilled workers say the U.S. tax overhaul poses little threat to Ireland, a preferred European home for the United States' top tech and pharmaceutical companies for a generation. They expect American companies to keep investing unabated in Ireland, with little incentive to move back to the United States.

The Emerald Isle's collective shrug when faced with the prospect of a lower U.S. corporate rate underscores why many experts are forecasting that the GOP tax plan will do little to alter the forces that drive American industry overseas. If anything, some argue, U.S. moves could make Ireland an even more attractive landing spot for members of the Fortune 500 in Europe.

The GOP tax plan moved closer to becoming law Wednesday after Republican negotiators in the House and Senate agreed on how to reconcile most of their differences. The goal is to send legislation to Trump next week.

The plan seeks to unlock the potential of $2.6 trillion that U.S. corporations have built up offshore for decades, many of them waiting for the United States to lower its unusually high rate of 35 percent on corporate profits. While most developed countries already tax the global profits of their homegrown companies, the United States long has allowed its multinationals to keep their income earned overseas and tax it only if they bring the funds home.

The proposed changes would slash the tax rate on U.S.-generated corporate profits to 21 percent, much more in line with international norms, and would slap immediate tax assessments on stockpiled overseas wealth, with a roughly 14.5 percent levy that would have to be paid within eight years. Future overseas profits would face a new rule requiring companies to pay a minimum of 10 percent on global profits, a measure that could take a slice from the money mountains sheltered in zero-tax Caribbean havens. As the theory goes, no longer able to avoid tax anywhere, U.S. corporate giants would feel liberated to invest those foreign gains on home soil.

But skeptics say the GOP tax bill is unlikely to change corporations' calculus about where they invest their money — for two basic reasons.

Why go home?

The first is that companies already have plenty of cash in the United States but may be choosing not to invest it because, according to many metrics, the U.S. economy is already near full capacity. So they will look for opportunities to invest abroad.

The second is that lawmakers have crafted the tax overhaul in ways that still create many incentives for keeping money abroad, particularly in places such as Ireland, which taxes companies at a rate of just 12.5 percent and admits foreign workers much more easily than the United States does — a particular attraction to firms looking for high-skill workers.

Tech workers taking lunch breaks on Dublin's Silicon Docks, so named because of the cluster of top U.S. social media and software companies lining the Grand Canal, articulate Ireland's appeal in a cacophony of languages. Here, workers are recruited seamlessly from throughout the 28-nation European Union, their entry requiring no work visas and meriting no hostility to immigrant labor.

Facebook workers, munching burritos on the waterside, chortled at the notion that their operations might relocate to the United States, given the need to keep expanding their sales and support teams from inside the E.U.'s single market.

"Every week, the list of new openings grows. We cannot hire people quickly enough," said Jan, a Danish worker for Facebook — which, like Twitter, Google and LinkedIn, established its European headquarters on Dublin's Southside, within a mile of all the others.

"This idea that Trump will somehow change the rules, and Facebook will be forced to airlift us to America, is not the real world," said Jan, who declined to give his last name because he did not have his employer's permission to speak to the media. He provides support to Facebook clients in Danish, Swedish, Norwegian, German and Dutch. "My job doesn't even exist in America," he said. "It belongs in Europe.

Facebook plans to expand its 2,200-strong Dublin workforce to 3,000 next year. Facebook and Google are actively seeking more Dublin space, while LinkedIn and Twitter have just moved into glitzy new Irish headquarters. They are among the most high-profile of more than 700 U.S. multinational corporations in Ireland that employ 150,000 people and generate more than 20 percent of the nation's economy, according to the American Chamber of Commerce Ireland.

Martin Shanahan, chief executive of IDA Ireland, the government agency tasked with securing foreign investment, said that American companies are being guided by market principles, "trying to acquire talent, trying to build global teams." The GOP tax plan "would leave companies free to use the capital wherever they want it."

Back in the United States, tax experts say the bill's proposal to start collecting at least 10 percent in tax on businesses' foreign profits could prove to be a mirage — and even create incentives to send more capital abroad.

Unlike a 2016 corporate tax proposal by President Barack Obama, the GOP plan would calculate that minimum tax on a global basis, not in individual countries. This could allow companies to keep stashing money in havens such as zero-tax Bermuda as long as they pay substantially more than 10 percent in other countries, such as France (33 percent) or even Ireland.

And the bill also leaves wide open the opportunity for U.S. companies to invest in new plants and facilities abroad. Such expenses will be deductible on advantageous terms that can be used to reduce the supposed 10 percent minimum tax, experts say, potentially making foreign operations more lucrative than their U.S. counterparts facing a 21 percent U.S. corporate tax rate.

As a result of those provisions, said Victor Fleischer, director of tax law programs at the University of San Diego School of Law, companies are still incentivized to locate factories and jobs in places that have a tax rate lower than the proposed U.S. rate of 21 percent. That includes not just Ireland but also Canada, Britain, much of Eastern Europe and Hong Kong.

Many companies acknowledge that they are not planning to invest more with their overseas funds. When Bank of America Merrill Lynch surveyed more than 300 top U.S. companies this summer about their plans, 65 percent said that any money they brought back to the United States would be used to pay down debt. The next most popular move was to buy back their own stock to drive up its value.

The United States is "already at low unemployment," said Rebecca Kysar, an international tax expert at Brooklyn Law School. "Doing a corporate rate cut at this time . . . is unlikely to result in a lot of job and wage growth in the United States."

The Trump administration and congressional Republicans dispute those views.

"We know for a fact that the studies show us [if] you lower the corporate tax rate, workers benefit," House Speaker Paul D. Ryan (R-Wis.) said Tuesday. "Think about if we don't do this and we keep the highest corporate tax rate in the industrialized world. We will have more companies leaving U.S. shores. . . . We will see more jobs going overseas."

A new boon possible

Ironically, Ireland — the only developed country Trump has singled out by name as undermining American competitiveness with its tax code — may turn out to be a winner if the tax plan takes effect.

Ireland has been criticized for years by political leaders on both sides of the Atlantic as a place where companies can deploy controversial tactics to avoid taxes.

After a string of U.S. drug companies switched their corporate headquarters to Ireland to reduce their tax bills in mergers with firms based in the country, the Obama administration in 2016 stepped in to stop Pfizer from doing the same "tax inversion" maneuver by blocking a merger with Dublin-headquartered Allergan.

Months later, E.U. competition authorities — who had spent two years investigating Ireland's tax treatment of Apple — ordered the tech giant to pay Ireland more than $15 billion in uncollected taxes dating to 1991. Apple has been in the southwest city of Cork since 1980 and employs more than 6,000 employees there.

Ireland joined Apple in appealing that judgment — even though receipt of such a vast sum could, in theory, allow the country to build 20 hospitals — arguing that the main country that should be taxing Apple's overseas profits is the United States. A new U.S. foreign tax would aid Ireland's case and reinforce its image as a keen recruiter for foreign investment, experts say.

"The Trump plan to make U.S. multinationals pay a minimum rate of tax on overseas holdings will take some of the pressure off Ireland to act like the tax policeman of the world," said Joe Tynan, who directs the 500-strong corporate tax team at PwC Ireland. "The E.U.'s been arguing that nobody has been taxing them properly. Well they will be now."

And Michael Mundaca, co-director of Ernst & Young's U.S. tax department and a former top tax official in the Obama administration, said that Ireland could benefit in other ways. With the U.S. corporate rate's drop to 21 percent, European countries with similar or higher rates will prove to be less attractive, making Ireland an even more popular choice for E.U. operations. "Ireland may be thinking, 'Hey, our advantage of having a lower tax rate just became even more important to U.S. companies,' " Mundaca said.

Privately, Irish leaders of American subsidiaries seem to be focused on saying nothing that might inspire a Trump tweet frenzy in their direction.

While the careers site of every U.S. multinational corporation in Ireland testifies to the thriving recruitment of techies, creatives and linguists from throughout the E.U. and beyond, the chief executives at some of these Irish offshoots say that they are not keen to spotlight rapid growth.

"We can't be seen to be taking a single job out of the United States, given the climate there," said one managing director of the Irish office of a leading American financial firm dedicated to servicing U.S. clients, speaking on the condition of anonymity due to the sensitivities of Ireland taking U.S. jobs or money.

"We keep hiring. Quietly."

Long reported from Washington.