Are illegals competing against union workers for labor,constuction & carpentry jobs?

Why do our union leaders give money to the democrat party so they can use their power to support the scab labor that is keeping union workers laid off? The Kennedy's prosecuted Hoffa, pardoned by a republican. Clinton sold unions out with the signing of NAFTA. Obama's "Cadillac" tax on our health insurance plans start in 8 years. Will union workers ever wake up and realize that democrats are killing our middle cl, our jobs and our country?