One of Ukraine’s greatest tragedies as it pursues a critical offensive that has, so far, failed to meet its own and Western expectations is that it cannot, by itself, decide its destiny.

President Volodymyr Zelensky’s government is dependent on a massive pipeline of US and Western armaments. And Russian President Vladimir Putin, whose historical obsessions and personal power calculations thrust Ukraine into this horrific war, will also have a great say in if and when it ends.

So, while battlefield sacrifices will decide how much seized territory Ukraine recovers, the outcome of the war will also be shaped by outside factors, including shifting political forces in the US, Moscow and European capitals.

A stalled offensive and a winter stalemate, for instance, would have particular ramifications in the United States since it could heighten questions over US support for the war that will be pushed into an acrimonious election year.

Americans are braced for a potential clash between President Joe Biden, who revived the Western alliance and is Ukraine’s most critical outside supporter, and ex-President Donald Trump, a NATO skeptic who admires Putin and has pledged to end the war in 24 hours, likely on Putin’s terms. And even if Trump is not the GOP nominee in 2024, ebbing public support for the war could hurt Biden.

Therefore, for political, as well as strategic reasons, there is huge pressure on Ukraine’s long-awaited counteroffensive this summer to produce significant battlefield breakthroughs.

But so far, the push is more of a slog than a blitzkrieg, raising the possibility the war could last at least deep into next year. If so, the elastic equation that underpins the entire conflict — involving Ukraine’s capacity to fight, Americans’ appetite for multi-billion dollar aid packages and Putin’s tolerance for horrendous casualties — will be even more taut.

Read Collinson's full analysis here.