According to Matt McKinnon, the Legislative and Political Director for the International Association of Machinists & Aerospace Workers, members of Congress who vote in favor of the NAFTA-style “free” trade agreements this week could draw union-backed primary challenges in 2012.  We interviewed McKinnon earlier — starting about 9 minutes in — while covering the Occupy D.C. events.

While President Obama has spent weeks crisscrossing the country publicly promoting his American Jobs Act, ironically in Washington his administration has been focused on lobbying Congress to approve a package of job-killing free trade deals. According to the Economic Policy Institute, the NAFTA-style South Korea Free Trade deal could cost America roughly 159,000 jobs while Colombia would export another 54,000.

After Obama announced that he would be sending the trade deals to Congress and abandoning his promise to insist on passage of assistance to displaced workers before doing so, I spoke with McKinnon at the Freedom Plaza event in support of #OccupyWallStreet.

I asked if the Machinists considered these bills a line in the sand with members of Congress.   McKinnon responded, “I will not tell you it is a cross the board thing but what I will tell you is that we will pick and choose and there will be some primary challenges.”

He also had choice words for a Democratic Party that saw its future in embracing such deals:  “If they offshore our work to South Korea it will never come back, and I don’t know how they win elections in the Midwest.”

With over half a million members spread throughout the country, the IAMAW has the potential to be a real force in many Congressional districts if they do get involved in primaries. The 2012 election should be a relatively very favorable cycle to launch primary challenges against incumbent House members.  The current Congressional job approval rating is historically low, so there is little love for incumbents right now.

More importantly, redistricting is taking place this cycle. This means in some of the redrawn districts a significant number of voters will not have been previously represented by the current incumbent. A sitting House member may not have the same built-in name recognition and loyalty with voters that are added to a newly redrawn district.

McKinnon would not say which districts they would be looking at, but he noted that states like Washington and Pennsylvania were places where the union had tremendous organizing capacity, but many members of Congress had bad voting histories on trade and other labor issues.