The Trans-Pacific Partnership (TPP) faces a difficult road ahead in Congress, with Senate Majority Leader Mitch McConnell, a fast track supporter, recently saying that the TPP couldn’t pass before the 2016 elections. A recent Reuters story speculated that, “Republican leaders intend to shelve the deal until after the November 2016 presidential election.”

For both political and substantive reasons, the odds for Congress to pass TPP before the end of this administration look long, and have grown longer over the past year.

According to Shane Larson, Legislative Director of the Communications Workers of America (CWA), “The opposition to the TPP is broad, deep, and bipartisan. Given the political climate in both parties, unresolved substantive concerns, and the raw vote counts in Congress, it is hard to imagine how this trade deal gets passed this year or next.”

According to Larson’s analysis, bipartisan political opposition to TPP from both parties’ leading presidential contenders is one reason TPP will be scuttled. Donald Trump, Ted Cruz, Hillary Clinton, and Bernie Sanders have all announced opposition to the TPP.

In addition, the vote count doesn’t add up in Congress to pass TPP. Earlier this year, fast-track trade promotion authority passed with just five votes to spare in the House of Representatives. A number of pro-fast track voters have announced opposition to TPP or expressed concerns about provisions included in the TPP text.

There are significant substantive concerns that threaten to flip pro-fast track voters against the TPP, according to Larson. How the TPP text treats tobacco companies is one point of divide among pro-fast track Republicans. Seventeen pro-fast track Republicans on the House Agriculture Committee signed a letter in October expressing concern about exempting tobacco companies from the TPP’s Investor-State Dispute Settlement (ISDS) provision.

Senator Thom Tillis (R-NC) noted, “This sets a dangerous precedent for future trade agreements, and I will not only vote against the TPP, but actively work to help defeat its ratification in the Senate.”

Other concerns that could help flip pro-fast track voters include the TPP’s provisions regarding currency manipulation, its treatment of biologics drugs, and bipartisan concern over the TPP’s automotive rules of origin provision, concerns over provisions dealing with agriculture and dairy products.

Supporters of the Trans-Pacific Partnership (TPP) claim that no trade agreement can force the U.S. to change its laws. “Recent World Trade Organization rulings against the U.S. country-of-origin labeling rules for beef and pork demonstrate that this claim is wrong,” said Larson. “In response to the WTO rulings, Congress has repealed COOL. Now, the TPP’s ISDS provision could provide a new mechanism to challenge U.S. laws and regulations.”