Hungary’s parliament is to vote Monday on ratifying Sweden’s bid to join NATO, likely bringing an end to more than 18 months of delays that have frustrated the alliance as it seeks to expand in response to Russia’s war in Ukraine.

Hungary’s government submitted the protocols for approving Sweden’s entrance to NATO in 2022, but the matter has stalled in parliament since then over opposition by governing party lawmakers. Unanimous support among all NATO members is required to admit new countries, and Hungary is the only one of the alliance’s 31 members that has not given its backing.

Prime Minister Viktor Orbán, a right-wing nationalist who has forged close ties with Russia, has said that criticism of Hungary’s democracy by Swedish politicians had soured relations between the two countries and led to reluctance among lawmakers in his Fidesz party.

But the vote on Monday is widely expected to approve Sweden’s membership in NATO, removing the final hurdle after it first applied to join the alliance in May 2022.