After three months of grueling fighting against Russian forces, Ukraine’s summer offensive is finally showing results, but not the dramatic breakthrough that Ukrainians and their supporters in the West were hoping for.

The Ukrainians’ goal was to penetrate Russia’s heavily fortified defense line in southern Ukraine and cut off the main roads between Russia and Crimea. They fought through the first of three Russian lines in late August and are now attacking the second.

That’s progress, but still far from where they wanted to be.

It has been a rupture, but not a breakthrough, says Michael Kofman, a military analyst at the Carnegie Endowment for International Peace who has made several visits to the conflict zone. Each day, progress is measured in hundreds of meters, not kilometers or miles, he said. It’s kind of a brawl.

Ukraine’s advance could still accelerate before ammunition runs out and winter arrives, Kofman added. Yet it is clear that this war will continue well into 2024, and likely beyond.

Ukraine’s leaders are determined to keep fighting because the alternative is their country being taken over by Russia’s Vladimir Putin. But their army has not yet advanced far enough for Putin to decide to cut his losses.

He is betting that the United States and its European allies will grow tired of sending money and weapons to Kiev.

Another reason for Putin to keep fighting is the prospect of Donald Trump possibly returning to the White House. Trump praised Putin’s invasion last year as genius and claimed that if elected he would end the war within 24 hours, which sounds like pulling the plug on Ukraine.

So it will take another year of fighting and presidential elections before Putin even thinks about negotiations.

Meanwhile, Ukraine needs help from the United States and Europe to keep fighting. Ukrainian President Volodymyr Zelensky will visit Washington this week to meet with President Biden and members of Congress.

One of his top requests to Biden will be regarding the US Army Tactical Missile System, also known as ATACMS (pronounced Attack Ems). The range of the missiles would allow Ukraine to hit Russian bases, equipment and ammunition far behind the front lines.

The Pentagon rejected the request, partly due to fears that Ukraine could use ATACMS against targets deep inside Russia, potentially triggering a superpower crisis. But in recent weeks, unnamed administration officials have said Biden is close to sending the missiles, a decision that could prompt other countries to send them as well.

But the ATACMS are unlikely to arrive in Ukraine soon enough to impact this summer’s offensive. Even then, they might not have made a decisive difference.

There is no silver bullet that will change the situation, said Alexander Vershbow, a former US ambassador to Moscow. But ATACMS could be useful during the winter in hindering the Russians’ efforts to rebuild their fortifications.

Meanwhile, Biden is asking Congress for another $24 billion in military and humanitarian aid for Ukraine. The proposal has drawn vocal opposition from pro-Trump Republicans, but with support from Republican hawks and Democrats, the proposal is likely to pass after vigorous debate.

Polls show that most voters are in favor of continued aid to Ukraine, but Republicans are increasingly opposed. A CBS News poll this month found that 54% of Americans support sending more weapons to Kiev, but 61% of Republican voters disagree.

Understandably, many Americans are tired of seeing taxpayer dollars spent on a distant war. The United States has already sent Ukraine more than

$50 billion in military aid.

So Biden should make it clearer that helping Ukraine is in the US national interest, not just an act of charity.

The president and his aides often cite a somewhat abstract principle to make their case: that major countries ruled by autocrats should not be allowed to invade their neighbors and seize territory.

But the stakes in this war also come down to realpolitik or, if you want to stick to English, hard reality. A Russian victory in Ukraine would be a disaster for the United States, a disaster even more damaging than our chaotic withdrawal from Afghanistan.

It would make Putin the strongman of Eastern Europe, able to intimidate his neighbors with the threat of more invasions.

And it would turn Russia’s three-way alliance with China and North Korea into a powerful axis of autocrats, reaching deep into Asia.

The US choice, in short, comes down to abandoning Ukraine and handing Putin a victory, or giving Ukraine a chance to keep fighting until Putin agrees to negotiate a reasonable peace.

These may not be palatable choices, but foreign policy usually is.

And as Zelensky said last week: it is not a movie with a happy ending.