Hillary Clinton still leads the race for the nod of Democratic caucus voters in Iowa, according to the latest Zogby poll. The survey, conducted November 6 of 502 likely Democratic caucus voters, measures voter preferences a week after an MSNBC Democratic debate in which Clinton had a much-publicized gaffe on the issue of New York State issuing drivers’ licenses to illegal immigrants.

Zogby measured Clinton’s support at 28 percent, followed by Barack Obama at 25 percent, John Edwards at 21 percent, Bill Richardson at 9 percent, Joe Biden at 3 percent, and Chris Dodd at 1 percent. Twelve percent were undecided.

Some national polls have seen a modest dip in support for Clinton this week—attributing it to her qualified support and “understanding” as to why New York Governor Eliot Spitzer backed a plan to give illegal immigrants drivers’ licenses in his state. Clinton was then criticized harshly by several of her Democratic debate opponents, as well as the media and several political strategists and commentators thereafter.

Iowans, like citizens of most of the nation, are generally supportive of tough action against illegal immigration. In an April 2006 Rasmussen poll, respondents favored sending National Guard troops to the U.S.-Mexican border by a 58-30 margin, wished to end the practice of giving citizenship to children born of illegal immigrants by a 63-23 margin, and were split 39-39 on the proposal to deport every single illegal immigrant out of the United States.

Republicans are more impacted by a candidate’s position on immigration policy in Iowa than Democrats. However, in a race in which Clinton’s lead has been in the single digits over both Obama and Edwards for most of the year, her immigration debacle could tip the scales. A September 2007 Los Angeles Times poll found 13 percent of likely Democratic caucus voters would only vote for a candidate who agrees with them on illegal immigration, compared to 34 percent of Republicans.

In a state that could deliver a knockout blow to the Edwards and Obama campaigns, Clinton strategists must be working overtime to insure a similar gaffe by their candidate doesn’t derail her lead in the Hawkeye States, now less tham two months before its caucuses.