* Obama campaign says Romney was failure as governor
* Obama strategist makes raucous appearance in Boston
* Romney visits Solyndra to attack Obama's economic approach
By Ros Krasny and Sam Youngman
BOSTON/FREMONT, California, May 31 (Reuters) - The campaigns of President Barack Obama and Republican Mitt Romney took their political gamesmanship up a notch on Thursday, with dueling events that featured raucous heckling, a secret trip for reporters and symbolic backdrops that reflected the increasing intensity of the tight race for the White House.
Obama's chief strategist David Axelrod invaded Romney's home turf, blasting the Republican's record as Massachusetts governor at an appearance in Boston where Axelrod frequently was interrupted by an organized crowd of heckling Romney supporters.
Romney retaliated a few hours later with an unannounced trip to the California headquarters of Solyndra, a solar panel company that went bankrupt despite receiving $535 million in loan guarantees from the Obama administration.
Romney's campaign went to great lengths to avoid the sort of heckling that greeted Axelrod, keeping the candidate's visit to Solyndra secret even from his traveling press corps until reporters were boarding the bus for the event.
"You saw what happened in Boston today," a senior Romney adviser said when asked about the secrecy.
The scenes on each coast highlighted the campaigns' battle of messages over jobs and the economy.
In Boston, Obama's camp argued that Romney's experience in Massachusetts was among many signs of the former governor's flawed favoritism of the wealthy.
Before a crowd outside the Massachusetts statehouse, Axelrod noted that the state ranked 47th out of 50 in job creation during Romney's four years as governor, from 2003 to 2007. He said the state's long-term debt grew and Romney broke a tax-cutting pledge by raising a range of fees that mostly hurt the middle class.
"Romney economics didn't work then and it won't work now," Axelrod said, straining to be heard over a group of chanting and heckling supporters organized by the Romney campaign.
Romney countered Axelrod's attack with the visit to Solyndra, which he said was evidence of Obama's poor economic leadership and his failure to understand how a free-market economy works.
"Free enterprise to the president means taking money from the taxpayers and giving it freely to his friends," Romney told reporters outside Solyndra's headquarters in Fremont, California.
"If the business had done spectacularly well, the shareholders - his friends - would have done very, very well but the taxpayers would have just gotten their money back," he said.
"On the other hand, of course, if the business failed, as it did, it's the taxpayers that get stuck with losing a half a billion dollars. So it's heads and his cronies win, and tails and the taxpayers lose."
Romney, who has said his real-world business experience makes him uniquely qualified to turn around the sluggish economy, said Massachusetts' unemployment rate had dropped to 4.7 percent while he was governor.
"My guess is the people of America would be very pleased if they could see a number like 4.7 percent," Romney said.
The exchanges on jobs and the economy, which polls show is the main concern of voters, came the day before the federal government releases its May jobs report. The U.S. unemployment rate was 8.1 percent in April, when job growth slowed sharply.
Romney clinched the Republican nomination this week with a victory in the Texas primary, although the race had been over for weeks as his remaining rivals suspended their campaigns.
Polls show Romney and Obama running neck and neck nationwide and in many of the crucial battleground states that will be essential to gathering the 270 electoral votes needed to capture the White House.
A NBC/Marist College poll released on Thursday showed Romney and Obama virtually deadlocked in three politically divided states - Iowa, Colorado and Nevada.
The Obama campaign has hit Romney hard for his years as head of the Bain Capital private equity fund, accusing it of bleeding jobs from companies to maximize profits before, in some cases, shutting them down.
The criticism has worried some Democrats who fear the attacks could turn off independent voters and be seen as criticism of free enterprise.
In Boston, Axelrod was joined on stage by a mix of Massachusetts Democrats, some of whom had served under Romney. Axelrod said manufacturing jobs disappeared during Romney's tenure at twice the national rate and that Romney had been about "taking what he can when he can."
He was frequently interrupted by the hecklers, who at times chanted "So-lyn-dra, So-lyn-dra."
Pointing to the hecklers, Axelrod said they were perhaps Romney's only backers in the state, where opinion polls show Obama with a big lead.
"It's a harsh judgment from the people who have come to know him best," Axelrod said.
At Solyndra, Romney defended the Boston hecklers and noted that he has been subjected to similar interruptions on the campaign trail by Obama supporters.
"Many of the events I go to, there are large groups of, if you will, Obama supporters there heckling me. And at some point you say, you know what, sauce for the goose is sauce for the gander," Romney said. "If they're going to be heckling us, why, we're not going to sit back and play by very different rules."
A senior adviser denied Romney's campaign was being paranoid in being so secretive about the visit to the Solyndra plant.
"Look, it's clear that they don't like questions being raised about Solyndra," the adviser said of Obama's campaign. "We're going to go right to the location itself. We thought the best way to do it would be with as little advance notice as possible."