Hillary Clinton is clinging to her small lead over Bernie Sanders in Iowa as their heated 2016 Democratic race for the White House officially kicks into gear this week when polls there open.

According to a Des Moines Register/Bloomberg Politics poll, the former secretary of state now snags 45 percent of the vote to Sanders' 42 percent. Those numbers reflect a three point upswing for Clinton since the poll was taken earlier this month, while Sanders is up by two points.

"This race is as tight as can be," said David Axelrod, a national political strategist. "If Bernie Sanders had momentum headed into the final month, the race now is static and essentially tied."

Axelrod, who served as chief strategist for President Obama during both his 2008 and 2012 campaigns, later added, "It comes down to who can grind it out on the ground on Monday night," emphasizing that turnout will be crucial.

"If turnout is within a normal range, Hillary likely wins," he reasoned. "If it goes higher, approaching 200,000, it will be a good night for Bernie."

Among voters insisting that they definitely plan to go to the polls, Clinton leads her rival and he holds a similar cushion among those indicating they will probably caucus.

A deeper analysis of the numbers reveals Clinton holds leads among voters 65 and older, Catholics and moderates, while the liberal Vermont Senator does best among those under 35, first-time caucus-goers and political independents.

"Clinton's voters are more certain and much more likely to have caucused before," Axelrod said. "Bernie's organizational task, counting so heavily on first-time caucus-goers - many of them young - is greater."

Clinton also garners the support of those who still believe the system works for those willing to invest in hard work, while Sanders excels among those who are convinced the system is rigged and society has become "grotesquely unfair," as he has previously lamented. Overall, about two-thirds of Democrats indicate they believe the system works against them.

"That theme is probably why this race is so close," said Ann Selzer, who conducts the Iowa Poll.

Former Maryland Gov. Martin O'Malley bags 3 percent of the vote, slightly down from the 4 percent he registered at in early January.

Related