An organized labor opponent will run television ads against Virginia's two Democratic senators, seeking to pressure them into opposing controversial "card check" legislation.

The National Right to Work Committee (NRWC) announced Monday it would begin running ads against Sens. Mark WarnerMark Robert WarnerOvernight Energy & Environment — Presented by American Clean Power — Dems see path to deal on climate provisions Sanders faces difficult choice on slimmed-down budget bill Overnight Energy & Environment — Presented by American Clean Power — Methane fee faces negotiations MORE and Jim Webb on the Employee Free Choice Act (EFCA).

While Webb is a previous supporter of the legislation, he hasn't sponsored the bill this term. Warner, a first-term senator, has also declined to sponsor the bill as of yet.

"The vote tally on this bill will likely come down to the wire, so Senator Webb