A little piece of sour candy from your friendly neighborhood eeyore to put you in the right frame of mind for tonight’s debate.

Second look at concentrating on House and Senate races?

There is evidence that the nation is becoming markedly more optimistic, and that Obama benefits from that attitude.

Thirty percent in the poll describe the economy as “good,” a 15-point increase since December and the highest level since the AP-GfK poll first asked the question in 2009. Roughly the same share say the economy got better in the past month, while 18 percent said it got worse, the most positive read in over a year.

Looking ahead, four in 10 said they expect the economy to get better in the next year and a third said they think the number of unemployed people in the U.S. will decrease, the highest share on either question since last spring. A quarter of those surveyed said they expect the economy to get worse over the next 12 months, while 31 percent said it would stay the same, the poll found.

As optimism has risen, Obama has received a corresponding bump in his approval rating for handling the economy. Forty-eight percent now say they approve of how he’s handling it, up 9 points from December.

The partisan split was 29D/25R/30I or, if you include some indies as leaners, 41D/40R. O’s 48 percent approval on handling the economy is the highest in nearly two years if you exclude his Bin Laden bump in May 2011; among independents, he’s at 49 percent. The same is true for his job approval on unemployment: He’s back to even at 49/49, which is not only the first time in years that he’s avoided net disapproval on that figure — again, excluding May 2011 — but the first time since June 2010 that his disapproval number has been below 50 percent. (Scan the crosstabs and you’ll find the Bin Laden bump affecting his numbers across the board.)

The bottom line:

Decent evidence that the conventional wisdom is right: For an incumbent to have a fair shot at reelection, the economy’s bottom-line numbers are less important than the trendlines. Last month’s drop in unemployment suggests a good trend, which translates here into a 6-7 point swing over two months in whether The One should be reelected. Is that good news for Santorum fans, since it weakens Romney’s supposed economic strength against Obama, or good news for Romney fans, since it suggests we should opt for the most electable possible candidate as Obama’s fortunes brighten? (58 percent of Republicans think Romney’s more electable versus 32 percent who say Santorum is.)