About 15 states and the District of Columbia want to intervene in a lawsuit over the legality of Obamacare's insurer subsidies.

The attorneys general for the states and the District filed a motion Thursday to intervene in the lawsuit between the House and the Trump administration, backing the legality of subsidies paid out to insurers in exchange for lowering copays and deductibles for low-income Obamacare customers.

"The Trump administration and Republicans in Congress are determined to repeal healthcare — through a vote in Congress, executive actions or litigation to sabotage the health insurance markets," according to a separate statement from the pro-Obamacare advocacy group Protect Our Care.

The House filed a lawsuit against the Obama administration in 2014 arguing that it bypassed Congress for paying cost-sharing reduction payments to insurers. The House argued that the payments needed to be appropriated by Congress, and the Obama administration said the subsidies should get a permanent appropriation like the law's tax credits.

A federal judge sided with the House last year but delayed her ruling from going into effect until after appeals were exhausted. The Obama administration appealed the ruling, but the Trump administration has not announced if it will continue the appeal or withdraw it.

It is not clear if the states have standing to intervene in the lawsuit.

The administration is paying the subsidies currently, but President Trump has said that he wants to see what happens with congressional efforts to repeal Obamacare before committing to the payments next year.

Insurers are pleading that they need some signal the payments will be there in 2018, as they are now formulating prices for plans to be sold in 2018.

Protect Our Care argues that the Trump administration and the Republican-controlled Congress are purposefully sabotaging Obamacare.

"Today's action represents an important strike against this sabotage," the group said.

A status report on the lawsuit from the House and the Trump administration is due Monday.