Turkey has ratified Sweden's NATO accession, leaving Hungary as the last holdout.
Should Sweden join the alliance, its control of the strategically important Gotland Island will give NATO control of the Baltic Sea, reversing the balance of power when it comes to a war in the Baltic States. Russia currently has "area denial" capabilities that would block NATO from reinforcing Estonia, Lithuania, and Latvia by sea, giving them the upper hand. But should NATO gain the ability to bring in maritime reinforcements then even the least defensible region under their vast security umbrella would suddenly become a lot easier to defend.
The EU has a liberal agenda while the Orban administration has a conservative agenda. This, combined with charges of authoritarianism in Hungary, have led to a growing rift between the two sides, with the EU attempting punitive measures to influence Hungarian national policies. As a countermove, Hungary has sought to leverage its position as an EU and NATO member to veto certain actions by these organizations, such as a $50 billion dollar aid package to Ukraine by the former and Sweden's accession to the latter.
Orban has paid lip service to not being opposed to Sweden's accession, and has pledged to ratify at some point, but in practice the ongoing dispute could prove an obstacle. There's a good chance the situation won't be resolved until Hungary is either cowed into submission or appeased with concessions.
