Mitt Romney's pollster tries to reassure supporters "Don't get too worked up about the latest polling," Mitt Romney's top pollster says in a memo sent to reporters and the campaign's donors. "Some voters" may be experiencing a "sugar-high from the conventions," pollster Neil Newhouse wrote. The basic structure of the race has not changed significantly. The reality of the Obama economy will reassert itself as the ultimate downfall of the Obama Presidency. Memos of that sort usually backfire - the fact that a campaign feels the need to publicly trumpet its lack of worry generally gets taken as evidence of the opposite. Whether Newhouse is right about the shape of the race should become apparent by the end of this week as more polling data become publicly available. For now, however, the polls that do exist look favorable for President Obama, who continues to enjoy a larger post-convention boost than Romney received. The latest national tracking polls show Obama holding a five-point lead over his Republican rival, 49%-44% in Gallup's survey, 50%-45% in the Rasmussen poll. Voters" rating of Obama's job performance also has improved in both surveys. Perhaps most ominously for Romney, Obama has demonstrated a significantly higher ceiling on his support, demonstrating that under the right circumstances, a significant number of persuadable voters will side with him. The numbers also indicate, however, that after three days of upward movement, Obama's post-convention increase has begun to level off. The key question now will be whether the increase turns out to have been a "bounce" that quickly goes back down, as Newhouse suggested it will, or a lasting increase that will put Obama in a strongly favored position. In some years, post-convention increases have dissipated quickly. In other years, including the 2004 election, a candidate has taken a post-convention lead and hung onto much of it. Romney's campaign, however, cites one historical precedent incorrectly. "Political campaign historians will recall President Jimmy Carter led Ronald Reagan by a near double-digit margin late in the fall in 1980," Newhouse asserted in his memo. In fact, as political scientist John Sides of George Washington University notes, polling averages show something very different - Reagan took a lead over Carter late in the spring of 1980, which then grew substantially after the Republican convention. Carter regained ground in the fall, but never fully overcame Reagan's lead. Twitter @DavidLauter