Various groups who are critical of the immigration bill that is now wending its way through Congress are accused of misrepresenting their motives.

The activist groups, NumbersUSA, the Center for Immigration Studies (CIS), and the Federation for American Immigration Reform (FAIR) favor lower legal and illegal immigration rates. In their efforts, they have sought out and received the support of Republican lawmakers.

NumbersUSA claims that 1.7 million of its members have contacted their members of Congress over the last 18 months to tell them not to support a bill that confers legal status on those who immigrated to the U.S. illegally.

The group says its members have faxed more than 34,000 pleas to Republican Sen. Marco Rubio of Florida alone since January. Rubio was one of the so-called Gang of Eight senators that drafted the bill.

However, critics of the groups accuse them of masquerading as conservative; alleging that they support an agenda of strict population control that also has included backing for abortion, sterilization and other policies that go against typical conservative ideology.

Mario H. Lopez, the president of the Hispanic Leadership Fund, writes, "Population-control advocates have built, operated, and funded much of the anti-immigration movement in the United States," essentially hijacking "concerns over immigration to advance their agenda."

As partial proof of these claims, critics assert that John Tanton, who co-founded FAIR and helped start Numbers USA and CIS, is a leader in the zero population growth movement.

Conservative leaders are trying to warn others about these groups. Kevin Appleby, the director of immigration policy for the U.S. Conference of Catholic Bishops, wrote in The Washington Post, "pro-life legislators should think twice about working with these groups, as their underlying goals are inconsistent with a pro-life agenda."