(Bloomberg) -- The US has criticized a new law that allows Poland’s ruling party to probe opposition leader Donald Tusk just months before a tightly contested election.

Ambassador Mark Brzezinski raised concerns about the legislation on Monday hours after President Andrzej Duda approved the creation of a special parliamentary panel to investigate Russia’s influence in Poland between 2007 and 2022.

The legislation grants the committee unprecedented powers, including the ability to effectively prevent officials from pursuing public office, bypassing the regular court system. Critics said the new panel aims to discredit and potentially bar key opposition politicians from taking part in October’s elections and marks further erosion of democratic standards by this government.

“The US government shares concerns about laws that could appear to allow for preempting voters’ ability to vote for the candidates of their choice outside of a clearly defined process in independent courts,” Brzezinski told private broadcaster TVN24. 

The comments are a rare intervention from the US envoy, who has largely praised Poland for its critical role in providing help to Ukraine since Russia’s invasion began last year. 

The government in Warsaw has sought to forge close ties with the US, including a deal to build the country’s first nuclear power plant and numerous orders for military equipment.

The country has also hosted President Joe Biden twice in less than a year, as it became the main gateway for aid and arms sent to Ukraine. 

Duda argued the new law is needed to explain the scale of Russia’s influence in Poland, which he described as a fact.

“Public opinion has to make up its own mind over the actions of the representatives they choose in the general election,” he told reporters.

Jaroslaw Kaczynski, the leader of the ruling Law & Justice party, has for years accused Tusk — his main political rival — of tolerating Russian influence during his tenure as prime minister before 2015. Parliamentary lawyers have attacked the law as a violation of European Union rules, while the country’s human rights ombudsman said parts of it violate the constitution.

Tusk said the law intends to “eliminate” the government’s biggest potential rival in upcoming elections and called its backers “cowards.”

The move places the issue of alleged Russian meddling front and center amid campaigning ahead of the vote slated for October, which may loosen Law & Justice’s grip on power. The government has blamed Russia for everything from spreading misinformation to being behind high inflation since the onset of war in Ukraine.

Duda said that while he’s signing the bill into law, he will also ask the country’s top court to review it, citing doubts some have over its compliance with the constitution. Brzezinski said the US is “well aware of the concerns expressed by many” and understands why the president wanted the court to weigh in.

(Updates with comments from envoy starting in the first paragraph.)

©2023 Bloomberg L.P.