For the first three years of the Obama administration the President's supporters pointed to 1984 as their model for reelection. There were some surface similarities. Both Reagan and Obama took office during terrible economic downturns. Both saw their parties loose in the first mid-term. What gave the Obama people hope is that the economy came surging back and Reagan easily won reelection. The only question on election night 1984 was if Mondale would carry any states?
With 100 days left before the election it is obvious that this year will not be a repeat of 1984. Unemployment is still high and the recovery is not robust enough to replace the lost jobs and keep up with new people entering the jobs market. Worse, the economy seems to be slowing down. While Obama leads Romney in most polls, the two are within the margin of error.
So now Team Obama is pointing to the 2004 election where Bush beat Kerry by a slim margin. Some commentators have remarked on the similarities of the two elections. I think that they are exaggerating this, possibly to give some hope to Obama supporters. In fact, once you get beyond the tight polls, there are not many similarities.
Bush had a modest recession and a major terrorist attack during his first term. He invaded two countries easily only to find that occupation is more difficult than invasion. The terrorist attack on 9/11 acted as a unifying event pushing Bush's approval ratings up. His party actually gained seats in Congress in the first mid-term. Bush's approval rating kept rising through his "Mission Accomplished" speech but started falling as the Iraqi insurgency got organized.
Obama had a major recession. There have been no unifying events like 9/11 under Obama. His approval rating started out high but dropped slowly over most of his term. Unlike Bush, Obama's party suffered major defeats in the mid-term election. Obama has not entered into any new wars but has moved military operations into new countries. These have been low-key and have not helped or hurt him in the polls.
Bush was always a moderate. He made an early attempt to work with the opposition and his pre-9/11 agenda (No Child Left Behind and the Medicare Drug Plan) had significant bipartisan support. These were big-government programs that could as eassily come from a moderate Democratic president. The main ways that the Bush administration was conservative were with social issues and with tax cuts.
Obama is an unapologetic liberal. His attempts to work with the opposition were pretty much limited to inviting Republicans to the White House to watch the Super Bowl. Shortly after that he lectured them, saying that elections have consequences and that "I won". His stated goal has been to change the course that government had been on since Reagan. His most significant accomplishment, Obamacare, passed without a single Republican vote and remains unpopular. Through unprecedented use of executive orders, Obama bypassed Congress on such things as immigration reform, welfare reform, and automotive mileage standards.
Bush's opponent is significantly different from Obama's, also. True, both have Massachusetts connections and come from wealthy families but the two are significantly different.
Kerry was the son of an ambassador and a long-time admirer of President Kennedy. He may have volunteered to captain a swift boat in order to emulate Kennedy who captained a PT boat. Kerry was never particularly wealthy until he married a rich widow.
In 2004 Kerry ran on his war record and wrapped up the nomination quickly. He continued to run on his war record through the convention when he took a ferry to the convention hall to remind people of his service in the navy. At his arrival he proclaimed that he was "Reporting for duty." This collapsed shortly afterwards when it turned out that his combat service had been limited to three months and he had spent the next few years as a war protestor. He had even symbolically returned his medals by throwing them at the White House (actually, he threw someone else's).
Kerry was from the far-left wing of the party with a voting record that made him the 3rd most liberal Senator. He often changed sides on specific bills over rarefied issues leading to his quote, "I was for the bill before I was against it."
Kerry's campaign was relying heavily on a CBS 60 Minutes story on Bush's military service. They planned on contrasting Kerry's time in combat with documents calling Bush a deserter. The 60 Minutes story was based on fabricated evidence which was obvious as soon as the story aired, leaving the Kerry campaign to try to find a different attack. They never did and the election came down to which side could mobilize its voters. Bush won with a convincing margin.
Romney's family fortunes varied from one decade to the next. His father did not become well-off until Romney was in high school and Romney earned his own wealth rather than inheriting or marrying it.
While Obama has tried to paint Romney as the most conservative Republican candidate since Goldwater, his record is as a moderate. Romney had problems winning the primary because conservative voters kept looking for a more conservative candidate. Only after it became obvious that Romney was the strongest candidate did the party rally to him. This could help Romney appeal to more moderate swing voters. The far-right may not have accepted Romney as Reagan's successor but they are motivated to vote against Obama. Any attempts at painting Romney as being far-right will probably help him with his base.
The issues in 2012 are completely different from 2004. In 2004 the economy was in fairly good shape. The insurgency in Iraq was still disorganized. The war in Afghanistan had been won so easily that no one was paying attention to it. Both Iran and North Korea were in talks to stop their nuclear programs. Bush was unpopular abroad among the general population but had a good working relationship with most foreign leaders. This allowed him to assemble a huge coalition for the invasion of Iraq. Bush is also regarded as the most pro-Israel president.
Most of the opposition to Bush came from hard-core Democrats who had never accepted his victory in the contested 2000 election.
In 2012, the economy is in poor shape. Obamacare is still unpopular. Talks with Iran and North Korea have collapsed and sanctions are failing but the Obama has no idea what to do next. Obama is popular abroad with the general population but has no relationship with foreign leaders. His actions have worsened relationships with such long-time allies as Canada (Keystone pipeline), Mexico (allowing drug lords to purchase American guns), and the United Kingdom. The Arab Spring seems to be producing anti-American Islamist governments. Obama is considered the least friendly president to Israel.
A president's second election is always a referendum on his first term. Obama is trying to deflect this through character assassination. Kerry did not have a good reason to replace Bush, all he had was harnessed Bush-hatred. Romney has the economy and his experience in business and as governor as reasons why he should replace Obama. This may not be sufficient but the 2004 election is no indicator.