* Ryan says he and Romney will make tough choices
* Biggest speech of career for Romney's No. 2
* Second night of convention opens with tribute to Paul
By John Whitesides and Matt Spetalnick
TAMPA, Fla., Aug 29 (Reuters) - Republican vice presidential contender Paul Ryan promised on Wednesday that he and running mate Mitt Romney would lead America out of the economic doldrums by making tough choices that would generate jobs and strengthen the middle class.
Ryan, a Wisconsin congressman, will accept his assignment as Romney's No. 2 at the Republican convention with the biggest speech of his political career - one designed to fire up conservatives while reaching out to independents still uncertain about the Republican team.
"We will not duck the tough issues - we will lead. We will not spend four years blaming others - we will take responsibility," Ryan will say later on Wednesday, according to excerpts of his speech released by Romney's campaign.
Ryan will join many of his fellow Republicans in criticizing President Barack Obama, promising he and Romney will repeal Obama's healthcare overhaul if elected.
"Obamacare comes to more than 2,000 pages of rules, mandates, taxes, fees and fines that have no place in a free country," he said in the excerpts.
Republicans hope to use the convention in Tampa, Florida, to show a softer side of Romney, who has had trouble connecting with voters, while focusing on his plans for an economic turnaround and criticizing Obama for lingering high unemployment and exploding deficits.
A Reuters/Ipsos online survey on Wednesday showed Romney already gaining a boost from the gathering. In the four-day rolling poll, Romney and Obama were deadlocked among likely voters at 43 percent each. That was an improvement for Romney from Obama's two-point lead on Tuesday and four-point lead on Monday.
"The convention is being seen and heard," said Julia Clark of Ipsos. "We can credibly say the slight change in the numbers can be attributed to the convention."
Romney's selection of Ryan, chairman of the House of Representatives Budget Committee, energized the party's core conservative supporters. They love his plan to rein in government spending and shift portions of Medicare, the popular health program for seniors, to a voucher system.
"I accept the calling of my generation to give our children the America that was given to us, with opportunity for the young and security for the old - and I know that we are ready," Ryan said in the excerpts. "Our nominee is sure ready. His whole life has prepared him for this moment - to meet serious challenges in a serious way, without excuses and idle words."
Ryan helps make a battleground of Wisconsin, which has not voted for a Republican presidential candidate since Ronald Reagan in 1984. A Romney victory there could alter the electoral map in a way that could hurt Obama's hopes for re-election.
Democrats have attacked Ryan as a conservative ideologue whose budget proposal would spell the end of Medicare. T he Obama campaign released an online video accusing him of harboring "out-of-step views from a bygone era" that would hurt the middle class, threaten Medicare and undercut women's abortion rights.
They hope to turn the Ryan plan against Romney in states like Florida, which has a large senior population, and Virginia, where thousands of government employees populate the suburbs outside the nation's capital.
The second day of the convention opened with a video tribute to Ron Paul, the libertarian Texas congressman whose disgruntled supporters caused a disruption at the convention on Tuesday in protest of new rules that could hurt similar grassroots movements.
Paul's son Rand, a Kentucky senator, also addressed the convention on Wednesday. Arizona Senator John McCain, the losing 2008 presidential nominee, and Condoleezza Rice, who served as secretary of state under former Republican President George W. Bush, were due to speak.
McCain and Rice are expected to take aim at Obama on foreign policy, which has taken a back seat to economic concerns at the convention and in the overall election campaign.
Romney waded into foreign policy on Wednesday at an American Legion gathering in Indianapolis, Indiana, trying to counter Democratic criticism of his inexperience abroad and accusing Obama of weakening America's place in the world.
"For the past four years President Obama has allowed our leadership to diminish," Romney said. "In dealings with other nations, he has given trust where it's not earned, insult where it's not deserved and apology where it's not due."
Romney denounced Obama's handling of both friends and foes of America.
"We used to nurture our alliances and stand up for our common values," he said. "But when it comes to friends and allies like Poland, the Czech Republic and Israel - and with nations that oppose us like Iran and Cuba - President Obama has moved in the opposite direction."
Foreign policy and military matters are points of vulnerability for Romney. A trip abroad last month aimed at burnishing his credentials was plagued by gaffes and stumbles.
Obama, whose own foreign policy inexperience was widely viewed as a weakness four years ago, now generally gets high marks in polls on the topic - particularly since the killing of Osama bin Laden last year.
With the convention shifting into high gear, delegates kept a wary eye on Hurricane Isaac as it pounded the Louisiana coast. There was concern that televised images of political revelry in Tampa could provide a jarring contrast to the storm's onslaught, although by Wednesday afternoon Isaac had been downgraded to a tropical storm.