* Two candidates both at 45 percent in poll
* Obama has room to grow this week
* Romney got modest improvement from convention
By Steve Holland
WASHINGTON, Sept 2 (Reuters) - U.S. President Barack Obama enters an important campaign week tied with Republican presidential nominee Mitt Romney, a Reuters/Ipsos poll found on Sunday, leaving the incumbent an opportunity to edge ahead of his opponent at the Democratic National Convention.
With the Democrats set to nominate Obama for a second term this week in Charlotte, North Carolina, the race to the presidential election on Nov. 6 is tight with 45 percent for Obama and 45 percent for Romney among likely voters, the survey found.
The findings were from the seventh day of a rolling online poll conducted for Reuters by Ipsos to judge voters' attitudes around the political conventions.
Obama campaigned in Boulder, Colorado, the state where he accepted the Democratic presidential nomination four years ago, while Romney was off the campaign trail in New Hampshire, about to begin preparations for three debates with Obama in October.
The Democrat is seeking to generate the same kind of enthusiasm that propelled him to the White House in 2008, a task that is much more difficult this time with Americans struggling under 8.3 percent unemployment.
While White House aides said on Sunday television talk shows that Obama would offer an economic path forward when he gives his acceptance speech this week, in Boulder he was still on the attack against Romney, criticizing the Republican National Convention in Tampa last week.
"Everything you heard from them ... you have heard before," the president told a large and supportive crowd at the University of Colorado. "They have tried to sell us this tired trickle-down, you're-on-your-own snake oil before," Obama said.
Obama's challenge is to show why four more years of his presidency would be better for the U.S. economy than his first term has been. His aides struggled to answer the question on Sunday, as to whether Americans are better off now than they were four years ago.
"We've made a lot of progress from the depths of recession. We have a lot more work to do," said White House adviser David Plouffe on ABC's "This Week."
Democrats argued that Obama inherited a bad economy from Republican President George W. Bush.
"What's happened since an election in 2008 and right now, again, is this huge economic calamity caused by a series of bad decisions that were made before the president ever got there," Obama campaign senior adviser Robert Gibbs said on CNN's "State of the Union. "This election was always going to be close because we live in a closely divided country."
A week ago, a Reuters/Ipsos poll said Obama led Romney 46 percent to 42 percent. The Republican's own convention gave him a small boost, vaulting him into an even position with Obama but no further.
Now Obama, who is to accept the nomination on Thursday, could get his own convention bounce. Ipsos pollster Julia Clark said Obama's numbers would likely improve during his convention.
"The fact that Obama and Romney are still tied signals to me that we're not going to see any sort of sustained bump for Romney," Clark said. "As we go into next week's convention, Romney will struggle to maintain even footing with the president - we'll likely see a shift back towards Obama."
While each candidate won overwhelming support from voters in his own political party, Romney was leading Obama among all-important independent voters by 33 percent to 28 percent, the poll found.
Romney's improvement on key attributes continued on an upward trajectory in the poll. On such issues as he "represents America," "is a good person," and "is eloquent," Romney was essentially tied with Obama. On who is more likable, Romney had improved but still trailed Obama 32 percent to 48 percent, the poll found.
ROMNEY SEEN AS MORE PERSONABLE
Republicans used their convention to play up the former private equity executive's family and personal life.
In Wolfeboro, New Hampshire, Mormon churchgoers at a service attended by Romney on Sunday thanked the former Massachusetts governor for raising the church's profile in his race for the White House and praised his nomination acceptance speech.
Romney, who would be the first Mormon president if he wins the election, sat smiling with his wife, Ann, as members of the Church of Jesus Christ of Latter-day Saints lauded his performance at the convention.
"To be honest the convention was pretty good for Romney," said Clark. "I think one of the big tests of the Republican convention was to make him more of a human, make him a little more personable, make him more likable. I think they succeeded there."
There has been no real movement in terms of candidate perceptions on any substantive policy areas such as healthcare, or even on which candidate is better in protecting American jobs. This underlines the notion that conventions are about style rather than substance, Clark said.
The poll suggested voters are waiting to hear what Obama has to say about the most pressing issue of the campaign, the U.S. economy.
Seventy-six percent of Americans believe the country is on the wrong track and 73 percent have a similar belief about jobs, the survey showed.
On the president's signature issue of his first term, healthcare, 62 percent believe the healthcare system is on the wrong track. Obama led an overhaul in 2010 of the U.S. healthcare system that Republicans deeply opposed.
Interest in the political conventions is high. The poll found 82 percent of registered voters have seen, heard or read at least something about the Republican convention.
But this dropped to 73 percent among independents and 66 percent among non-aligned registered voters, those who are undecided about how to vote or who say they will not vote.
This suggests that the groups candidates most need to target are not yet engaging with the electoral process, Clark said.
The rolling poll measures sentiment during the two-week convention season by polling over the previous four days.
For the survey, a sample of 1,441 American registered voters was interviewed online. The precision of the Reuters/Ipsos online polls is measured using a credibility interval. In this case, the poll has a credibility interval of plus or minus 2.9 percentage points for all respondents.