Bulgaria is increasingly pursuing a transactional foreign policy that risks weakening European cohesion, according to a new analysis by the European Council on Foreign Relations (ECFR), as Prime Minister Rumen Radev seeks to balance ties with the United States while distancing Sofia from key European security initiatives.

The report was published after Sofia's decision to host US military refuelling aircraft at Bezmer Air Base, that elevated the geopolitical pressures facing the EU and Nato member.

In its July 23 analysis, ECFR said Radev's recent foreign policy decisions reflected "a growing inconsistency in Bulgaria's strategic posture" that could complicate European efforts to build a more coordinated defence policy.

The think-tank noted that Bulgaria recently withdrew from the European "coalition of the willing" supporting Ukraine while simultaneously agreeing to host up to eight US Air Force KC-135 refuelling aircraft for operations in the Middle East.

"Rather than aligning with the broadly pro-European consensus and anti-American sentiments in Bulgarian society, Radev is attempting to balance competing security frameworks without sufficiently considering European security interests," the report said.

According to the ECFR, the Bulgarian leader has attempted to limit the domestic political cost of supporting the US deployment by referring the decision to parliament, allowing him "to spread the political responsibility and limit direct ownership of the move."

The report argued that Sofia's position reflected a broader trend among some European governments seeking bilateral arrangements with Washington as US President Donald Trump pursues a more transactional foreign policy.

"As the Trump administration continues to conduct foreign policy through bargaining, some European governments appear tempted to pursue bilateral arrangements with Washington rather than invest in European unity," the report said. "Such behaviour risks weakening collective defence, precisely when strategic coordination is needed."

The ECFR urged Brussels to respond by engaging more actively with Sofia rather than allowing strategic ambiguity to deepen.

"European security cannot rely on member states choosing cooperation only when politically convenient," it said.

The report called on the European Union to "engage more actively with the Bulgarian government and push back on Radev's form of hedging while political conditions remain favourable," while strengthening incentives for participation in common defence initiatives through the EU budget and defence instruments.

It also warned that external powers could exploit divisions within the bloc, pointing to what it described as Russia's growing influence in Bulgaria after Sofia reportedly sought to remove two Russian businessmen and a senior Russian Orthodox cleric from the EU's latest sanctions package.

"The EU should treat Bulgaria as an urgent political case rather than a lost cause," the report said, warning that elections across Europe in 2027 could further complicate efforts to maintain a common foreign and security policy.

In recent days tensions with Iran have intensified following Bulgaria's decision to host US aircraft supporting operations in the Middle East.

Iran's embassy in Sofia issued its third warning to Bulgaria on July 27, saying Bulgarian leaders would "bear responsibility for the dangerous decision to deploy a US aerial refuelling aircraft to their military bases" and accusing Sofia of facilitating US military operations.

The warning followed a July 22 parliamentary vote authorising the deployment of up to eight KC-135 refuelling aircraft and as many as 250 US military personnel at Bezmer Air Base until October 1 under a bilateral defence agreement with Washington.

US President Donald Trump publicly thanked Radev for supporting the deployment despite Tehran's objections, further highlighting Sofia's importance in US regional logistics.

Bulgarian officials have sought to calm concerns, insisting the deployment does not make Bulgaria a party to the conflict. Security officials told a government meeting on July 27 there was no direct threat to the country's security, while authorities said they had strengthened security around Bezmer Air Base and remained in close coordination with Nato allies. A Nato spokesperson also said the alliance would defend Bulgaria against any retaliation linked to the deployment.

The foreign policy debate has coincided with slipping public support for Radev's government. A Market Links poll published on July 23 showed the prime minister's approval rating falling to 50% in July from 53% in June and 56% in May, while disapproval rose to 33%.

Pollster Dobromir Zhivkov said voters were increasingly concerned by what they saw as inconsistent government positions on Russia, Ukraine and the deployment of US aircraft at Bezmer, arguing that the administration appeared to be reacting to events rather than pursuing a coherent strategic direction. Despite the decline, Radev remained Bulgaria's most trusted political figure, according to the survey.