Will US aid help turn tide on Russia?
It's been around a year since Ukraine was in final preparations for its much-touted spring counteroffensive against Russia.
The aim was to breach Russian lines and recapture large swathes of occupied territory. But despite a surge in military support from the West, the counteroffensive did not live up to expectations and Ukraine failed to push back Russian forces.
Our military analyst, Sean Bell, says Ukraine has provided an "incredibly robust defence" since then, but a long delay by US Congress in passing a multi-billion dollar aid package for Kyiv has "taken its toll".
"Ukraine has lost ground on the frontline and Russia has momentum, which has impacted Ukrainian morale and cost lives," he explains.
So will the US decision to provide $60bn of military aid turn the tide in Ukraine's favour? This is among the topics discussed by Bell in this week's Red Matrix podcast.
Russia could make advances this summer
Momentum is vital in warfare, Bell says, and Russia has plenty of this after capitalising on Ukraine's much-publicised shortage of weapons to target its energy infrastructure, cities and the frontline.
Despite heavy Russian casualties, Bell says Vladimir Putin will want to seize the window of opportunity to inflict more losses on Ukraine "before US military aid can be brought to bear".
"Many military analysts believe that Russian advances in key sectors of the frontline look likely to be repeated this summer as there is increasing evidence that Russia is preparing for a large-scale summer offensive," he says.
Putin's long game
Mr Putin is preparing for a long war which will eventually see Western support for Ukraine wane, Bell says.
"Russia has more soldiers, has tripled the size of its defence industrial base to create a sustainable supply of weapons... and can fund the war through huge and sustainable oil revenues," he explains.
Ukraine, meanwhile, is "critically dependent" on Western aid.
Despite the contrast in military might, Bell doesn't anticipate a strategic Russian breakthrough - with Moscow's battlefield success "not a foregone conclusion".
He points to recent comments from Volodymyr Zelenskyy, who said Western allies can defend Ukraine in the same way they defended Israel from a recent Iranian attack.
"Why not afford Ukraine the same level of support?" says Bell.
Western hesitation emboldens Putin
The West "has the military might to stop Russia's invasion in its tracks", says Bell, but has so far been deterred by escalating Russian rhetoric.
But longer it "tolerates" Russia's actions, the more emboldened Mr Putin will become, making him a "more dangerous threat to the West in the coming years", he adds.
Regardless of the US's huge military aid package for Ukraine, Mr Zelenskyy and his forces look to be in for a "very difficult spring and summer", Bell says.
