Labour shadow chancellor John McDonnell has promised to support strikes.
Such support can make a real difference to whether workers feel confident enough to strike.
But it also pokes at one of the party’s biggest divisions.
Labour has always had a difficult relationship with strikes. Although individuals, and sometimes leaders, have backed disputes, the party itself has never officially supported a strike.
That’s because Labour has always seen parliament as the most important battlefield.
Getting elected and governing means proving that Labour is “responsible”. So even some of Labour’s earliest MPs shunned strikes in favour of “constitutional” parliamentary action.
During the great Miners’ Strike of 1984-5 Labour leader Neil Kinnock denounced miners’ “violence”.
And when Ed Miliband was asked about the public sector strikes against Tory pension attacks in 2011, he criticised “both sides”.
Left wing shadow justice secretary Richard Burgon was asked on Tuesday whether he’d support workers if they defied the Tories’ draconian anti-union laws.He couldn’t give a straight answer.
It’s always welcome when MPs such as McDonnell throw their support behind strikes.
But as pressure grows for public sector pay strikes, activists must look to their own strength while using the backing from Labour MPs.