It's just a short walk to cross the floor in the Senate.

From where Fatima Payman started her journey to where it ended, mere dozens of steps were needed.

But each step "felt like a mile", the Labor senator told reporters after she defied her party and voted with the Greens calling for the recognition of Palestinian statehood.

The scale of her actions can't be measured in the number of steps.

On paper, Payman is the embodiment of some of Australia's most marginalised people: She is young, she's Muslim, she wears a hijab and is a woman.

Diminutive in size, she stared down a party machine and defied those who wanted her to toe the line.

Labor supports a two-state solution in the Middle East. Senate Leader Penny Wong unsuccessfully sought to water down the Greens' motion to recognise a state of Palestine, prompting the government to ultimately vote against the motion.

Speaking afterwards, Payman said she crossed the floor to represent the core values of the Australian Labor Party — equality, justice, fairness and advocacy for the voiceless and the oppressed.

"I walked with my Muslim brothers and sisters who told me they have felt unheard for far too long," she said.

"And I walked with the people of Palestine, for the 40,000 killed, for the hungry and scared boys and girls who now walk alone without their parents and for the brave men and women who have to walk alone without their children.

"I walked for humanity. I am proud of what I did today and am bitterly disappointed that my colleagues do not feel the same way."

Threats to cross the floor are far from new.

Just think back to the Coalition's years in power, when there was no shortage of Nationals threatening to cross the floor. As it turned out, time and time again, it proved more sizzle than steak. Had they done it, it would have brought with it few consequences.

Crossing the floor is allowed in the Coalition. Take Barnaby Joyce, whose days crossing the red carpet floors didn't stop him later becoming Australia's deputy prime minister. A virtue in the Coalition, it's a no-go in Labor.

It's so rare that when the last Labor politician crossed the floor in government, Payman, 29, wasn't even born yet.

The consequences could have cost her seat in Labor's party room, something Payman was reminded of before the vote.

That she followed through when many haven't, speaks to the significance of the decision.

After the vote, the government was quick to insist that expulsion wasn't a "mandated sanction", essentially guaranteeing Payman would remain in the party's ranks. On Wednesday afternoon, after meeting with Payman, Albanese said the senator wouldn't attend caucus meetings for the next week.

Likely, there was little Labor could do. The optics of booting Payman from the party would only further fuel resentment among those who wish Labor was doing more.