WARSAW, Poland (AP) — Voting has begun in a high-stakes election in Poland that will chart the way forward for the European Union member on NATO’s eastern flank.

The outcome of Sunday’s election will determine whether the right-wing Law and Justice party will win an unprecedented third straight term or whether a combined opposition can win enough support to oust it.

A referendum on migration, the retirement age and other issues is being held at the same time, which the opposition says is an effort to mobilize the ruling party’s electorate.

Many Poles feel like it is the most important election since 1989, the year that marked the end of decades of communism. The health of the nation’s democracy, its legal stance on LGBTQ+ rights and abortion, and the foreign alliances of a country on NATO’s eastern flank that has been a crucial ally to Ukraine, are all at stake.

Political experts say the election will not be fully fair after eight years of governance by Law and Justice that has eroded checks and balances to gain more control over state institutions, including the courts, public media and the electoral process itself.

Some 29 million Poles aged 18 and above are eligible to vote.

They will choose 460 members of the lower house, or Sejm, and 100 for the Senate for four-year terms.

More than 31,000 voting stations across Poland will be open from 7 a.m. to 9 p.m. (0500-1900 GMT) on Sunday. Over 400 voting stations will operate abroad.

Exit poll results by global polling research firm Ipsos will be announced on state broadcaster TVP and commercial stations TVN and Polsat when polls close at 9 p.m. (1900 GMT). The margin of error is plus or minus 2 percentage points.

Individual parties need to get at least 5% of votes to win seats in parliament, coalitions need at least 8% of votes.