WASHINGTON -- US Secretary of State Marco Rubio heads to Sweden on May 21 for a meeting of NATO foreign ministers as European allies seek reassurances over US troop drawdowns and Washington's shifting rhetoric on the alliance.Rubio will attend the gathering in Helsingborg on May 22, one of the final senior-level ministerial meetings before alliance leaders convene for a summit in Ankara in July.According to the State Department, the top US diplomat is expected to press allies for higher defense spending and "greater burden sharing" while also focusing on Arctic security.But the meeting comes at a moment of deep unease. European officials are seeking clarity on how much Washington plans to scale back its military presence on the continent following a series of abrupt Pentagon moves that have rattled the alliance.'Kept In The Dark'The uncertainty stems from recent announcements that have raised fears across Europe that Washington may be weakening its security guarantees at a dangerous moment.Earlier this month, US President Donald Trump announced plans to withdraw 5,000 troops from Germany. The Pentagon later confirmed it was canceling a planned rotational deployment of roughly 4,000 troops to Poland and shelving plans to deploy a battalion of ground-launched Tomahawk cruise missiles to Germany.A senior European diplomat, speaking to RFE/RL on condition of anonymity, warned that the alliance's core deterrence was being undermined by a lack of communication."The worst thing is the fact that the continent is seemingly being kept in the dark about the scope of this drawdown," the diplomat said, noting that frontline states such as the Baltic countries are struggling to plan.The diplomat added that reported US plans to reduce contributions to NATO's force model -- under which members pre-commit forces for major crises -- would "make a considerable dent" in Europe's initial defense lines."NATO's effectiveness rested on the idea that it was unbreakable," the diplomat said. "Now, in a divorce, you start to see the cracks appearing."Administration officials have insisted the moves are temporary adjustments rather than a strategic retreat. US Vice President JD Vance recently said the administration's focus remains on "European independence and sovereignty," while Pentagon spokesman Sean Parnell described the Poland decision as a "standard delay in rotation."Rubio As The 'Steady' MessengerFor many European officials, Rubio's presence offers a measure of reassurance. The top US diplomat is widely viewed in Brussels and Eastern European capitals as a steadier and more traditional transatlantic figure than some others in the Trump administration.Congressman Don Bacon, a Nebraska Republican, and staunch NATO supporter, told RFE/RL that Rubio plays a key role in stabilizing relations. Bacon said he hoped Rubio would reinforce Washington's commitment to collective defense while urging European allies to increase defense spending.Bacon has repeatedly argued that alliances remain central to US security interests and warned against isolationism amid growing threats from Russia, China, and Iran.