Washington (CNN) Donald Trump and Hillary Clinton start the race to November 8 on essentially even ground, with Trump edging Clinton by a scant two points among likely voters, and the contest sparking sharp divisions along demographic lines in a new CNN/ORC Poll.

Trump tops Clinton 45% to 43% in the new survey, with Libertarian Gary Johnson standing at 7% among likely voters in this poll and the Green Party's Jill Stein at just 2%.

The topsy-turvy campaign for the presidency has seen both Clinton and Trump holding a significant lead at some point in the last two months, though Clinton has topped Trump more often than not. Most recently, Clinton's convention propelled her to an 8-point lead among registered voters in an early-August CNN/ORC Poll. Clinton's lead has largely evaporated despite a challenging month for Trump, which saw an overhaul of his campaign staff, announcements of support for Clinton from several high-profile Republicans and criticism of his campaign strategy. But most voters say they still expect to see Clinton prevail in November, and 59% think she will be the one to get to 270 electoral votes vs. 34% who think Trump has the better shot at winning.

Neither major third party candidate appears to be making the gains necessary to reach the 15% threshold set by the Commission on Presidential Debates, with just three weeks to go before the first debate on September 26.

The new poll finds the two major party candidates provoke large gaps by gender, age, race, education and partisanship. Among those likely to turn out in the fall, both candidates have secured about the same share of their own partisans (92% of Democrats back Clinton, 90% of Republicans are behind Trump) but independents give Trump an edge, 49% say they'd vote for him while just 29% of independent voters back Clinton. Another 16% back Johnson, 6% Stein.

Women break for Clinton (53% to 38%) while men shift Trump's way (54% to 32%). Among women, those who are unmarried make up the core of her support, 73% of unmarried women back Clinton compared with just 36% of married women. Among men, no such marriage gap emerges, as both unmarried and married men favor Trump.

Younger voters are in Clinton's corner (54% to 29% among those under age 45) while the older ones are more apt to back Trump (54% to 39% among those age 45 or older). Whites mostly support Trump (55% to 34%), while non-whites favor Clinton by a nearly 4-to-1 margin (71% to 18%). Most college grads back Clinton while those without degrees mostly support Trump, and that divide deepens among white voters. Whites who do not hold college degrees support Trump by an almost 3-to-1 margin (68% to 24%) while whites who do have college degrees split 49% for Clinton to 36% for Trump and 11% for Johnson.

Support for Johnson seems to be concentrated among groups where Clinton could stand to benefit from consolidating voters. Although direct comparison between the poll's two-way, head-to-head matchup and its four-way matchup doesn't suggest that Johnson is pulling disproportionately from either candidate, his supporters come mostly among groups where a strong third-party bid could harm Clinton's standing: Younger voters (particularly younger men), whites with college degrees, and independents, notably.

The poll follows several national polls in August suggesting that the margin between the two candidates had tightened following the conventions. A CNN Poll of Polls analysis released Friday showed that Clinton's lead had been cut in half when compared with the height of her convention bounce.

Speaking to reporters aboard her campaign plane Tuesday, Clinton shrugged off a question about the CNN/ORC survey.

"I really pay no attention to polls. When they are good for me -- and there have been a lot of them that have been good for me recently -- I don't pay attention," Clinton said. "When they are not so good, I don't pay attention. We are on a course that we are sticking with."

While enthusiasm for the campaign has continued to inch up, it remains well off the mark compared with this point in other recent presidential election years. In the new poll, 46% say they are extremely or very enthusiastic, compared with 57% at this point in 2012, 60% in early September of 2008 and 64% in September 2004.

Further, nearly half of voters say they are less enthusiastic about voting in this election than they have been in previous years, while just 42% say they're more excited about this year's contest. Although this question hasn't been asked in every presidential election year, in CNN/ORC and CNN/USA Today/Gallup results dating back to 2000, this poll marks the first time that a significantly larger share of voters say they are less enthusiastic about this year's election. The lack of enthusiasm spikes among Clinton supporters. A majority of Clinton's supporters say they're less excited about voting this year than usual (55%) while most of Trump's backers say they're more excited this time around (56%).

That could be contributing to Trump's slim advantage among likely voters. Among the broader pool of registered voters, Clinton edges Trump by 3 points. The shift among these voters since the convention is largely due to a rebound in Trump's numbers rather than a slide in Clinton's. He's gone from 37% support then to 41% among registered voters now.

Trump holds an edge over Clinton as more trusted to handle two of voters' top four issues -- the economy (56% trust Trump vs. 41% Clinton) and terrorism (51% Trump to 45% Clinton). Clinton holds a solid edge on foreign policy (56% trust her to Trump's 40%), and the public is divided over the fourth issue in the bunch, immigration. On that, 49% favor Clinton's approach, 47% Trump's. At Trump's recent campaign appearances, he has argued that he would do more to improve life for racial and ethnic minorities, but voters seem to disagree, 58% say Clinton is better on that score vs. 36% who choose Trump, and among non-whites, 86% choose Clinton to just 12% who think Trump would better improve their lives.

Trump has his largest edge of the campaign as the more honest and trustworthy of the two major candidates (50% say he is more honest and trustworthy vs. just 35% choosing Clinton) and as the stronger leader, 50% to 42%. Clinton continues to be seen as holding the better temperament to serve effectively as president (56% to 36%) and better able to handle the responsibilities of commander in chief (50% to 45%).

On honesty, Clinton's backers express greater skepticism about their candidate than do Trump's supporters. When asked which candidate is more honest and trustworthy, 94% of Trump's backers say he is, while just 70% of those behind Clinton choose her, with 11% saying Trump is more trustworthy and 17% saying neither of them are. And when voters were asked to name the one issue that would be most important to their vote for president, 5% named honesty or trustworthiness as their top choice, ranking it on par with foreign policy and jobs.

Both candidates remain largely unliked, with majorities saying they have an unfavorable view of each candidate in the new poll.

The CNN/ORC Poll was conducted by telephone Sept. 1-4 among a random national sample of 1,001 adults. The survey includes results among 886 registered voters and 786 likely voters. For results among registered or likely voters, the margin of sampling error is plus or minus 3.5 percentage points.

Correction: The CNN/ORC Poll topline document released Tuesday contained an error, numbers showing the partisan makeup of the sample on the methodology page were transposed. The correct party makeup of all adults in the poll is 32% Democratic, 28% Republican, 40% independent or something else. This is a similar Democratic tilt to the previous CNN/ORC Poll, in which 28% of respondents described themselves as Democrats and 24% Republicans and on par with the average across all CNN/ORC Polling conducted this year, which yields a 5-point Democratic advantage."

Among those determined to be likely to vote, 36% described themselves as Democrats, 32% as Republicans.