A group of largely Republican-led states is taking aim at the Biden administration with a fresh lawsuit to end the COVID-19 mask mandate on public transportation.

On Tuesday, 21 state attorneys general, all Republicans, filed a lawsuit against the mask mandate, arguing that the policy is "shortsighted" and "heavy-handed." They castigated the mandate as a burden on interstate travel by creating “chaos” while leaving passengers frustrated.

"It's long past time to alleviate some of the pressure on travelers and those working in the travel industry by immediately ending Biden's unlawful public transportation mandates," said Florida Attorney General Ashley Moody in a statement.

The mask mandate on public transit was among President Joe Biden’s chief moves to institute public health measures nationwide in his first year in office. As the administration begins to shift towards a lighter touch and preventative approach to managing COVID-19, a bipartisan assortment of states have begun moving in a similar direction.

Republican states began reducing public health restrictions before their Democratic counterparts, but the federal mandates have been a point of contention for several of them. Republican governors have sued the Biden administration over vaccination mandates for state National Guard members while dozens sued Biden over an executive order calling on all private employers to mandate vaccinations against COVID-19.

This effort was defeated after being taken all the way to the U.S. Supreme Court, which ruled against the administration.

Mask mandates on public transport have been contentious in many cases. In the case of mask mandates on airlines, there have been countless cases of flights being diverted over passengers who refused to comply or who became violent towards other fliers or staff.

However, the push to pull back mandates has not only been pushed by politicians. On March 23, the chief executives of several large airlines wrote a letter to Biden that urged him to end the federal mask mandate and pre-departure testing requirements for international travel.

"It makes no sense that people are still required to wear masks on airplanes, yet are allowed to congregate in crowded restaurants, schools and at sporting events without masks, despite none of these venues having the protective air filtration system that aircraft do," the airline letter said.