So why have fewer MPs backed it, compared to a year ago?
There are a number of reasons why support for assisted dying has dropped off.
Some MPs have changed their mind. Janet Daby, the Labour MP for Lewisham East, for example told the Commons that after she previously backed the bill “my conscience was not at peace, and I cannot again, in good conscience, vote for the bill.”
But in reality those switching their position are a small minority.
For others, the influence of Andy Burnham may have been a factor. When MPs last gave their collective view on assisted dying, Sir Keir Starmer was prime minister and supportive of this bill.
Burnham, however, is not. For Labour MPs wanting to follow Downing Street’s priorities, abstaining might have seemed a more appealing option.
There will be other reasons why supportive MPs did not turn up today. A wedding, I’m told, took some away from Westminster. A trip to Ukraine meant others missed the vote.
Already those in favour of a change in the law promise to try again. Kim Leadbeater, the Labour MP who introduced the original legislation last year, has told the another attempt could come as soon as next year.
Supporters have told me they see this parliament, with such a large proportion of Labour MPs who tend to support assisted dying, as a “unique moment” to pass this change.
“This result doesn’t mean there isn’t still a majority in parliament in favour of the principle of assisted dying,” said one of those behind the bill.
But for now the momentum has fallen away from a change in the law.
That is a relief to those who worry such a change would risk harming vulnerable people. But it is a bitter disappointment to those who see it as a necessary and compassionate alternative to the status quo.
That bitterness from supporters is aimed in part at the House of Lords.
It was opponents’ efforts there that ultimately led to this defeat. And it could hasten those calling for reform of Parliament’s second chamber.