Once appointed Slovakia's prime minister, Robert Fico wasted little time in reiterating the nationalist populist agenda that propelled him to victory in the country's September 30 election.

"You'll hear a sovereign Slovak voice from Slovak ministries and watch a sovereign Slovak foreign policy," Fico declared.

It's a pledge that's in line with his campaign promises, which mixed extremist and pro-Russian narratives. And there's plenty of concern that Fico's return to power, five years after he was ousted over the murder of journalist Jan Kuciak, could help to undermine unity in the European Union and NATO.

If his rhetoric is anything to go by, Fico could, with the help of his disinformation-peddling foreign minister, Juraj Blanar — who for instance claimed Ukrainians were responsible for the 1968 Soviet invasion of Czechoslovakia — try to derail Western support for Ukraine or sanctions against Russia.

Another concern is that Fico's election could give fresh impetus for Hungarian Prime Minister Viktor Orban, who by some is accused of seeking to establish an illiberal pro-Russian bloc within the EU.

But there's also doubt whether Fico has the clout to have significant impact, or even if he'll really follow through on his threats once he's away from the eyes and ears of the extremist cohort he courted to win back the prime minister's chair.

Alarm over NATO's security interests

While Fico doesn't question Slovakia's membership in the EU or NATO, the leader of the nominally Social Democratic Smer party was swift to pay lip service to his election pledges on the European stage.

At an EU summit the day after his appointment, he told European Commission President Ursula von der Leyen that Slovakia would send no weapons to Ukraine nor support new sanctions against Russia.

It's the sort of talk that powered his remarkable political resurrection.

"This reflects the views of a significant part of the Slovak population, who traditionally have held a more favorable view towards Russia compared to most regional peers in Central and Eastern Europe," points out Andrius Tursa, an expert on Eastern Europe with risk consultancy company Teneo International.

It's little surprise then that the new Slovak leader's performance provoked alarm in some quarters when it comes to NATO's security interests.

"Since Slovak soldiers are placed in Latvia … can we trust that they will be allowed to fight if Latvia is invaded by Russia?" asked former Latvian defence minister Artis Pabriks. "Can we trust [the] Fico government? Can NATO trust [the] Fico government regarding sensitive intelligence."

Too small to disrupt Western unity?

Others say that, with a population of just 5.5 million and a €115 billion ($122 billion) economy (GDP in 2022) heavily dependent on EU partners, Slovakia is simply too small to disrupt Western policy.

"Slovakia is such a piddly country that this will barely make a difference," one EU official said according to Politico. "Slovakia barely has any leverage."

Even disregarding such anonymous trolling, there's reason to expect Fico will follow a more moderate course behind closed doors, as he did during his previous stints as premier, asserts Milan Nic, an Eastern European and Russia specialist at the German Council on Foreign Relations.

The extremist rhetoric is fashioned for the Slovak audience, analysts say, not as a message to foreign partners.

Indeed, Fico has many reasons to tone down his language in Brussels. He takes the reins with Slovakia in a perilous financial position, and desperately needs EU recovery funds and cohesion funds if he's to offer voters the stability and prosperity he has promised.

"Fico is a pragmatist. He knows that without EU funds Slovakia will not be stable," says Grigorij Meseznikov at the Slovak Institute for Public Affairs.

He will therefore want to avoid attracting attention to his antics on the domestic front, says Nic, where he does pose a significant risk to the rule of law. Poland and Hungary have had funds worth billions frozen over similar.

Illustrating this balancing act, Fico failed to follow Orban's lead in opposing the EU’s proposed €50 billion aid package for Ukraine, saying financial aid for Ukraine depends on guarantees that European money will not be embezzled and that Slovak companies take part in the restoration of Ukraine.

"As long as they [EU leaders] say the wrong things and do the right things, I think it's fine," Estonian Prime Minister Kaja Kallas said after a meeting with Fico on the sidelines of the summit.

Many note that, despite the delays and niggles, Orban has backed all of the bloc's support measures for Ukraine and sanctions packages against Russia.

Fico's empty threats

Fico's pledge Slovakia will not send "another bullet" to Ukraine is also viewed largely as an empty threat because the country has already sent practically all the arms it could anyway.

Even Russia admits that it will make little difference.

"Slovakia did not have such a big share in the supply of weapons, so it will hardly affect the entire process," the Kremlin's spokesperson said following Fico's summit announcement.

Meanwhile, Slovakia's privately-owned weapons industry, which has large orders from Western countries, including Germany, to produce and ship weapons to Ukraine, looks set to continue sending arms across the eastern border.

Parliament speaker Petr Pellegrini said he doesn't expect such shipments to be affected by Fico's promises, noting the important economic role that Slovakia's arms industry plays.

No trolling

All of which suggests that Fico is unlikely to boost Orban's hopes of building an alternative power bloc inside the EU.

Fico noticeably failed to back Hungary when it opposed the aid package for Ukraine at the summit — a bid by Budapest to get some of its own funds unfrozen.

In another negative signal for Orban, Fico made sure to tell everyone in Brussels that he won't be copying the Hungarian's trolling of Western partners by meeting with Russian President Vladimir Putin.

But even if Fico does play ball, it won't make up for the loss of Poland for Orban.

Under nationalist populist Jaroslaw Kaczynski, Poland has joined Orban in confronting the EU over the past eight years. But with liberal factions set to take power following Poland's own elections last month, the Hungarian prime minister is looking more isolated.

"Unlike Orban and Kaczynski, Fico has no vision of politics as a force for change," says Meseznikov. "He seeks power for its own sake. He'll work with Orban in a bid for back up on certain issues but won't actively work towards building an illiberal block."

A strong message from Brussels

All that said, Fico's victory is still clearly a setback for the EU and NATO.

It has symbolic value for Putin, who will enjoy pointing at further divisions, while the potential is there to "complicate decision-making at the EU level on issues that require consensus," says Tursa.

With this in mind, Meseznikov insists Slovakia's Western partners must be firm to keep him in line.

"I don't think Fico will moderate significantly on his own. He still sees the partial success Orban has had in defying the West and will perhaps think he can repeat the trick," the analyst says.

"But if Brussels and Berlin quickly send him a strong message that his antics won't be tolerated, then his excesses could be limited."

Edited by: Andreas Illmer