AS COLUMNS of soldiers marched through the centre of Kiev to mark 25 years of Ukrainian independence this week, Larissa Nikitina could not help but think about the price of sovereignty. Some 9,500 Ukrainians have been killed in fighting in the country’s east since early 2014, and there are more casualties every week. “We fought for this holiday, we are fighting for it, and we will have to keep fighting for it,” she said. Tensions have flared around Crimea and eastern Ukraine in recent weeks, and many worry that another round of fighting is on the horizon.

The Minsk peace process, which has sought since mid-2014 to broker an end to the conflict, has been at a standstill all summer, and violence has been escalating. International monitors have noticed Ukrainian government and Russian-backed separatist forces creeping closer along the line of contact; heavier-calibre weaponry and artillery have come back into use. Earlier this month, Russia claimed that Ukraine tried to stage a terrorist attack on Russian-occupied Crimea, a charge Kiev denied. While events remain murky, Vladimir Putin’s rhetoric was ominously clear: “We will not let these things pass.” Ukraine’s president, Petro Poroshenko, put his troops on high alert.

Ukraine’s worries have been compounded by Russian sabre-rattling along its borders. Mr Putin led a meeting of his security council in Crimea last week, as the Black Sea Fleet staged war games. Large-scale exercises in the Southern Military District, encompassing Crimea and part of the border with Ukraine, are scheduled for September. Ukrainian observers have noted that Russian exercises provided cover for assaults on Ukraine in 2014 and Georgia in 2008.

Nonetheless, an all-out invasion by Russia remains unlikely. The Pentagon says it has not seen evidence of “troop movements that are so large that we’re concerned about those on their own”. Occupying Ukrainian territory would be bloody and costly. “Russia could enter, but getting in does not mean getting out,” says Colonel General Ihor Smeshko, a former head of Ukraine’s Security Service (SBU). Partisan resistance would be fierce. And Ukraine’s army, while still lagging Russia’s, has improved from the hollowed-out force it was when Russia annexed Crimea in early 2014. Then, Ukraine could field just 6,000 combat-ready infantry. During the ensuing war, officials say, some 300,000 soldiers have seen time on the frontline.

Instead, Russia hopes to use the threat of war to extract concessions at the negotiating table. “Tensions along the border create a discourse in the West and Ukraine,” says Alex Ryabchyn, a Ukrainian MP from the Donetsk region. “Putin wants the West to think about what would happen if war restarted.” The agreements require Ukraine to hold elections in the secessionist territories, but are ambiguous about the sequencing. Moscow accuses Kiev of balking. Ukraine and the West insist that a stable ceasefire and the withdrawal of Russian forces must come first.

Pressing forward with the political elements of the Minsk protocol carries grave domestic risks for Ukraine’s leadership—a fact not lost on the Kremlin. When constitutional amendments foreseen under the Minsk deal were first raised in parliament last summer, nationalist protests outside the Rada turned violent, leaving four dead. Passing election laws and constitutional changes while soldiers are still dying in the Donbas would be “disastrous” for Ukraine’s political stability, says Ivanna Klympush-Tsintsadze, the country’s Vice Prime Minister for European and Euro-Atlantic Integration. While the West often pushes for more compromise, she adds, “there are serious red lines” where Ukraine cannot make further concessions.

Ultimately, Russia may be seeking a favourable renegotiation of the whole peace deal. As diplomats bicker over a “road map” for implementation, Russian propositions amount to a “rephrasing” of the original Minsk agreements, says Sergei Rakhmanin, deputy editor of Zerkalo Nedeli, a Ukrainian weekly. Mr Putin has accused the Ukrainians of “turning to terror” and abandoning the Minsk plan, and suggested that further meetings in the Normandy negotiating format of Russia, Ukraine, France and Germany are senseless. When Angela Merkel and François Hollande meet Mr Putin on the sidelines of the G20 summit on September 4th, they may do so without Mr Poroshenko.

For Russia, the time to regain advantage by changing facts on the ground appears ripe. More military drama would provide a welcome distraction from Russia’s economic struggles ahead of its mid-September parliamentary elections. Barack Obama wants to get closer to resolving the Ukraine crisis before his term ends. Ms Merkel and Mr Hollande are eyeing their own upcoming elections next year, and remain preoccupied with the fallout from the migrant crisis and Brexit. The current timetable for Minsk implementation will run out at the end of the year, as will European Union sanctions against Russia.

The West will need to muster political will to extend both. Many expect pressure to escalate further before talks in Minsk on August 26th and at the G20 on September 4th-5th. Ukrainians believe the aim is to lure them into overreacting. “They’re trying to provoke us to go on the attack and give them a reason to abandon Minsk,” says Yuri Biryukov, a presidential advisor. With so many men and so much materiel along the front, even small provocations risk spiralling out of control.