For the first time in the five polls conducted monthly by American Research Group (ARG) since December 2006, John Edwards is now polling ahead of Hillary Clinton among likely Democratic caucus voters in Iowa.

Edwards received 27 percent of support in the poll, conducted April 27-30, with Clinton coming in at 23 percent. Clinton dropped 11 points since a mid-March ARG poll; Edwards, meanwhile dropped 6 points from his 33 percent level of support in March. More Iowans are now undecided about which candidate they support (16 percent) than in any of the previous ARG polls, including twice as many undecided likely voters as compared to 5 months ago (just 8 percent in December 2006).

Senator Clinton held double digit leads over Edwards in December (11 points) and late January (17 points), but Edwards has since closed the gap: down 4 points in February, 1 point in March, and now up 4 points in the new survey.

Iowa is considered to be a must-win state for Edwards. The former Senator has campaigned heavily in the Hawkeye State since the 2004 election, and will need the momentum (and the positive press coverage that accompanies such a victory) to compete with the well-funded Clinton (and once buzz-worthy Barack Obama) heading into New Hampshire and the big multi-state primary days that take place a few weeks later.

Obama came in third in the new ARG poll at 19 percent. The two candidates who enjoyed the biggest surge of support, however, were in the “second tier” of candidates. Joe Biden received the support of 6 percent of likely Democratic caucus voters, after polling at just 2 percent in each of the previous four ARG surveys. Bill Richardson likewise polled in fifth place at 5 percent, after receiving just 1 percent in the four previous polls.