The recent arrest of Indian diplomat Devyani Khobragade has unleashed two kinds of outrage: protests by Indians upset over her treatment by New York police, and, mostly outside of India, anger over Khobragade’s alleged crime of forcing a domestic employee to work long hours for a fraction of the prevailing wage after having pledged in a visa application to follow US labour and wage laws.

Less attention has been paid, however, to a more insidious problem: how international diplomatic practice and US immigration law enable the abuse of domestic workers.

Many diplomats, whether foreign or US, consider it a right to employ domestic help while on assignment overseas, bringing servants with them as part of their household. US law has two specific visa categories to allow this: one for representatives of foreign governments and another for those working for international organisations.

For the 2012 fiscal year, US consular officers issued visas to 1,871 domestic employees accompanying foreign diplomats on assignment to the US.

The US law requires the employer to pay the greater of minimum or prevailing wage and limit regular scheduled time to 40 hours a week. Let’s be realistic, however: If the employer really intended to respect normal US wage and working conditions, wouldn’t they be more likely to hire locally rather than importing domestic help?

Cultural sensitivities or the need for foreign language skills may sometimes make local hiring a challenge, yet most areas where embassies or consulates are located have significant pockets of nationals from the country in question. Moreover, many domestic employees are third-country nationals themselves, often hired shortly before their employer’s overseas assignment.

Beyond occasional news reports and hearsay, documenting the extent of the abuse of such domestic workers is difficult. The deck is heavily stacked against complaints by poor foreign workers whose livelihood and visa status — and occasionally the safety of their families back home — depend on the good will of an employer protected from prosecution by diplomatic immunity.

In 2008, the US Government Accountability Office reported 42 documented cases of abuse of domestic employees by foreign diplomats in the US since 2001. The actual number of incidents was “likely higher”, it said, and would probably increase as more scrutiny drove the problem further underground.

In a final twist, US citizens who reside abroad but are temporarily returning to the US (even for several years) may also bring home foreign domestics on a regular visitor visa. Normally, only US diplomats and high-level employees of multinational companies will meet the conditions to sponsor a domestic.

The employee must have at least one year of experience, including six months with the US employer, and a signed employment contract with wage and termination provisions stipulated by regulation.

Given the economic calculus, it’s no surprise that abuses occur. Except in the rare cases where the foreign domestic is already a beloved member of the family — an attachment that tends to require a lot more than six months to form — the servant is being brought to the US because doing so is cheaper than hiring locally or using locally available day-care resources.

The William Wilberforce Trafficking Victims Protection Reauthorisation Act, passed by Congress in 2008, provides tools to combat abuse of domestic employees.

The basic inequality of the employer-employee relationship, however, unfortunately allows for coercion in many cases that can undermine the act’s protections — a concern that Congress has expressed as recently as last year.

Advocacy groups have called for the lifting of diplomatic immunity in such cases. Yet nations sharply disagree over immunity’s provisions and protections, and they are not shy about retaliating in ways that can jeopardise larger relationships, as we saw this week with reports that Energy Secretary Ernest Moniz postponed a long-scheduled trip to India in response to rising tensions in the Khobragade dispute.

A better approach would include more rigorous enforcement of the Wilberforce Act.

The US could also shine more light on abuse simply by having the State Department release its annual report to Congress on court cases where diplomatic immunity has been called into play — a naming and shaming tactic that the department has so far been reluctant to pursue. It could also give the issue more prominence in its annual human trafficking report.

Of course, the US could simply stop giving visas to foreign domestic workers of diplomats. Unfortunately, rewriting US immigration law is rarely straightforward. It is also likely to trigger unintended diplomatic consequences.

Even so, the Departments of State and Homeland Security could act now to eliminate the administrative loophole that allows foreign domestic workers to enter the US and work for both Americans and foreign diplomats on temporary visitor visas with their lesser protections.

That would be a useful first step in ending US complicity with employment arrangements that, in practice, often violate its labour laws and commitments to uphold basic human rights.—By arrangement with Washington Post-Bloomberg News