Canada's trade deal with the European Union was signed last October, but its ratification is neither sealed nor delivered.

Members of the European Parliament vote Wednesday around noon local time (6 a.m. ET) following a final debate at their plenary session in Strasbourg, France.

With the fate of the Comprehensive Economic and Trade Agreement (CETA) hanging in the balance, observers trying to get an accurate read on the head count say it might be close.

Canadian officials have consistently expressed optimism that enough members of the European Parliament (MEPs) have been won over.

One positive sign for the officials is that International Trade Minister François-Philippe Champagne is on his way to Strasbourg to be present for the ratification vote.

Prime Minister Justin Trudeau takes off tomorrow and is scheduled to speak to parliamentarians Thursday to celebrate and promote the new deal.

Canadians grinned with relief when the Comprehensive Economic and Trade Agreement was signed Oct. 30. (Francois Lenoir/Reuters)

Criticism of the deal also persists.

Greenpeace campaigners dressed like Mounties were working EU hallways last week handing out lollipops to deliver their message that "CETA sucks."

We're in the European Parliament giving MEPs a sweet reminder to vote no to <a href="https://twitter.com/hashtag/CETA?src=hash">#CETA</a>! <a href="https://t.co/h1IpaoZBGj">pic.twitter.com/h1IpaoZBGj</a> —@GreenpeaceEU

If a majority of the 751 legislators vote against CETA, the deal fails. It won't matter that all 28 member states (eventually, in Belgium's case) gave it their blessing for signature last fall.

Could that happen?

The debate in several European Parliament committees offered a mixed preview.

The employment and social affairs committee recommended against ratifying in December.

The environment, public health and food safety committee voted in favour of ratifying a few weeks later.

The trade committee's blessing on Jan. 24 paved the way for Wednesday's plenary vote.

Socialists and Democrats key

The largest political group in the European Parliament, the European People's Party (217 seats), supports CETA.

There's more at stake than just trade <a href="https://twitter.com/hashtag/CETA?src=hash">#CETA</a> <a href="https://t.co/SjjJtZyJhS">pic.twitter.com/SjjJtZyJhS</a> —@EPPGroup

The third- and fourth-largest blocs, the European Conservatives and Reformists and Alliance of Liberals and Democrats, are also expected to vote in favour.

.<a href="https://twitter.com/Europarl_EN">@Europarl_EN</a> will be voting on <a href="https://twitter.com/hashtag/CETA?src=hash">#CETA</a> this week. <a href="https://twitter.com/hashtag/tradeforjobs?src=hash">#tradeforjobs</a> <a href="https://t.co/C69POzaBNl">pic.twitter.com/C69POzaBNl</a> —@ecrgroup

On the other side, Green MEPs as well as far-right nationalist MEPs (think Nigel Farage, Marine Le Pen) are expected to oppose.

3.5 million citizens said no to <a href="https://twitter.com/hashtag/CETA?src=hash">#CETA</a> on <a href="https://twitter.com/eci_ttip">@eci_ttip</a>.<br>Read our letter to <a href="https://twitter.com/JustinTrudeau">@JustinTrudeau</a> on why we'll say the same: <a href="https://t.co/Xehrt3B3IC">https://t.co/Xehrt3B3IC</a> <a href="https://t.co/1qhSJtpG3f">pic.twitter.com/1qhSJtpG3f</a> —@GreensEP

That leaves the second-largest bloc, the 189 votes of the Alliance of Socialists and Democrats (S&D) as the key swing voters. Some are under pressure from socialist allies and trade unions in their respective countries to vote against.

The group met late Tuesday and about 65 per cent of the MEPs in the room voted in favour of CETA, suggesting a similar split outcome in tomorrow's plenary.

After a long, "intellectually rich" debate, CETA advocate and Romanian MEP Sorin Moisa said this split was slightly better than he was expecting.

"CETA is an important step, whether they vote for it or not, in creating a more progressive trade policy," he said.

PM Justin Trudeau tells high school students how committed Chrystia Freeland was in getting the CETA deal passed with the E-U, to the extent of having a bbq in her own backyard for a number of important guests. 1:42

Moisa believes Canada's commitment to improve the investor court provisions and conduct an early review of the enforceability of the deal's sanctions on labour and environment helped win over skeptics.

So did a strong desire to signal empathy and solidarity with Canada in the face of President Donald Trump's aggressive protectionism in the U.S.

"The trend he represents is different from the trend represented by CETA," Moisa said.

CETA bill clears Commons

If Wednesday's vote succeeds, Canada and the EU have agreed to provisionally apply over 90 per cent of the deal within months — the parts deemed entirely within the EU's legal jurisdiction.

The rest waits for ratification votes in individual countries.

Canada's implementation bill, C-30, passed at third reading on Tuesday afternoon. It now proceeds to the Senate.

Bill C-30 makes legal and regulatory changes to bring Canada into compliance with CETA.

International Trade Minister Francois-Philippe Champagne is on his way to Strasbourg to represent Canada as the European Parliament votes on CETA ratification. (Jeff McIntosh/Canadian Press)

Canada's provinces and territories — Quebec in particular — also must change laws and regulations to comply. None have signalled they won't co-operate.

Provisional application takes effect after an exchange of diplomatic notes to say these processes are complete.

Most of the advantages Canadian businesses could enjoy from CETA — tariff elimination, market access, government procurement opportunities and harmonized regulations — kick in with provisional application.

The deal could be in force provisionally for years if full ratification proves difficult.

Activists targeting future votes

Fresh images from Washington Monday of Trudeau and Trump smiling and shaking hands became fodder for critics who fear CETA gives U.S. corporations a back door into Europe through Canadian subsidiaries.

Happy valentine's day Trump & Trudeau, your passion for bad trade deals like <a href="https://twitter.com/hashtag/CETA?src=hash">#CETA</a> is everlasting. Please leave us out of your relationship! <a href="https://t.co/X2F0VMpqvc">pic.twitter.com/X2F0VMpqvc</a> —@eci_ttip

Social media Tuesday showed anti-CETA groups mobilizing for yet another protest on the streets outside the vote.

Maude Barlow from the Council of Canadians tells CBC News she won't be among them, despite her organization's continuing campaign.

"It is going to pass," she wrote, "but not by the kind of margin it should, given the time it has taken to negotiate and all the effort that has gone into promoting it by the powers that be.

"Really it should be a landslide for them and it won't."

H-3 avant l'arrivée à Strasbourg ! Cette année on célèbre la <a href="https://twitter.com/hashtag/SaintValentin?src=hash">#SaintValentin</a> en tête à tête avec le <a href="https://twitter.com/hashtag/CETA?src=hash">#CETA</a> <a href="https://twitter.com/hashtag/MakeLoveNotCETA?src=hash">#MakeLoveNotCETA</a> <a href="https://t.co/CC2GPj1mow">pic.twitter.com/CC2GPj1mow</a> —@attac_fr

Barlow said she's saving her energy for the next fight: votes and possibly referendums in 27 out of the 28 member states.

"CETA opponents only need one 'no.' CETA proponents need 38 'yeses,'" she said, referring to all the legislatures across Europe (plus regional governments in Belgium) that will hold ratification votes.

If MEPs shut down this treaty first, it wouldn't be unprecedented.

In 2012, the controversial Anti-Counterfeiting Trade Agreement (ACTA) was defeated after too much skepticism swept across Brussels.

Trudeau's plane doesn't leave until midday Wednesday — just in case, perhaps.