Races are tight — or at least growing tighter — in two swing states. Here's our guide to today's polls and why they matter. 

Findings: In two polls out of Ohio today, Obama leads Romney narrowly 48 to 45, while another have the two tied at 45 percent each. 
Pollster: Public Policy Polling, Rasmussen
Methodology:  PPP, which shows the 3-point Obama lead, used an automated survey of 961 likely voters and had a margin of error of +/-3.2 percent.  Rasmussen was also automated, and had 500 likely Ohio voters with a margin of error of +/-4.5 percent. 
Why it matters: Whoever wins Ohio will probably win the election and both campaigns are fighting hard for the state. NPR explains that the coal country in the eastern part of the state, where Romney hosted a campaign stop today, is crucial for the Republican: "he nearly lost the Ohio primary in March to former Pennsylvania Sen. Rick Santorum, primarily because of Santorum's strong showing in eastern Ohio." 
Caveat: PPP leans Democratic, Rasmussen the opposite. Also, PPP's poll began before Paul Ryan was announced as Romney's vice president pick. Rasmussen's poll was conducted entirely after that announcement and found 51 percent had a favorable opinion of the vice presidential pick. Still, both polls are, if you take margin of error into account, essentially ties. 


Findings: Obama's lead has dwindled in New Hampshire to 6 points, 51 to 45 percent, down from a 12 points in May. 
Pollster: Public Policy Polling
Methodology: Automated calls to 1,055 likely voters with a margin of error of +/-3.0 percent.
Why it matters: Obama won the state 54-45 in 2008, and it's one of the states he probably plans to retain in his re-election strategy. But Romney has some natural advantages in the state: much of New Hampshire is in the Massachusetts media market, so he's a familiar face from his time as governor and, as The Hill points out, he keeps his vacation home there, too.    
Caveat: The race in the Granite State could be even closer than this: yesterday the University of New Hampshire Survey Center found Obama leading 49 percent to 46 percent. And there's the Ryan factor: part of the polling was done before the announcement and almost a third of voters hadn't yet formed opinions on him. Also, as noted above, PPP is a Democratic outfit.