London (CNN) Theresa May will have woken up Wednesday morning hoping she has won back something she lost last night: Her voice.

Her hoarse, cracked tones in Parliament as she addressed lawmakers following yet another humiliating defeat underlined the great personal pressure the Prime Minister is under on Brexit.A good night's sleep may have soothed her vocal cords, but it will not have restored parliamentary support for her Brexit deal -- that may be lost altogether.

The result, a defeat by a margin of 149 votes, will be near-impossible to reverse.

With 16 days left before the UK is due to leave the European Union, the Brexit rollercoaster lurches once again as lawmakers prepare to vote on a motion to prevent no deal.

A meaningless vote?

On a similar vote last month, the House of Commons signaled its opposition to a no deal Brexit.

Yet this time, it's more complicated: Facing the risk of her Conservative party splitting in two, the Prime Minister has agreed a free vote on the motion -- meaning the party's lawmakers are not obliged to follow the government's position.

Many Conservative MPs (members of Parliament) already favor a no deal -- because it would deliver the hardest Brexit possible, with no ties at all to the EU after March 29. This group is likely to have increased in number after Tuesday night's defeat of May's plans, with MPs now fearing that unless they vote for a no deal, Brexit itself could be delayed -- or canceled altogether.

For businesses, lawmakers and government officials who fear a no deal cliff-edge will damage the UK economy and cause panicked stockpiling of foods and medicines and long queues at the border, the prospect of Parliament actively voting for this scenario is very worrying indeed.

The Prime Minister, unsurprisingly, will vote against a no deal. And yet, regardless of the outcome of Wednesday's vote, Britain is heading for a no deal Brexit anyway -- because that is the default position, unless a deal can be agreed by both Brussels and the UK parliament.

In one sense, after Tuesday night's so-called meaningful vote, Wednesday's is the meaningless vote.

Delaying Brexit

The only way lawmakers can now stop a no deal is for one or more of three things to happen: May's plan to pass in another vote, for a different exit plan to be backed by a majority of the Commons, or for Parliament to pass a motion to delay Brexit.

The first of these options would involve yet another meaningful vote -- following one back in January, in which May's plans were defeated by a majority of 230, and the vote last night, featuring a tweaked version of her original withdrawal agreement, containing additional legal language on the Irish backstop.

Tuesday's vote was rejected by 391 votes to 242, with 75 Conservatives MPs rebelling against May.

It is possible, although not likely, that the Prime Minister will wait until closer to exit day, when the Commons is running out of alternative options, to present her plans for a third time.

But, given the appetite among her Brexiteer lawmakers for a no deal, it is very unlikely this would pass.

And given May's strategy of presenting Parliament with an ultimatum -- of her deal or no deal -- has effectively failed, this tactic to further run down the clock will enrage MPs who already think she should step down as Prime Minister.

What is more likely is one or both of the second and third of these options.

A vote to delay Brexit is expected Thursday, and will be a close-run thing.

Crucially, however, both a new deal and a delay would need approval from Brussels in order for them to change the course of Brexit.

Next week, EU leaders are gathering for the last summit before Britain's departure date -- so UK lawmakers would need to agree a position before then.

On Tuesday night, MPs from different parties and factions began to table amendments to Wednesday night's no deal motion in order to make the vote have some force.

There are still moves afoot for a second referendum, which could pave the way for Brexit to be canceled altogether.

But there are also now Conservative MPs openly discussing May's departure because of her failure to secure backing for her Brexit deal. She is going to need to be in strong voice for the days ahead.