Before Barack Obama gave his speech on Monday explaining his decision to attack Libya, he already had trouble with voters on national security in Rasmussen’s polling, scoring only a 43% approval on the issue against 37% who rated him as poor.  Obama’s speech had an impact, but not the one he’d hoped, and not just on national security:

Although President Obama made an address to the nation Monday night to explain his decision to commit U.S. military forces to Libya, fewer voters than ever give him positive grades on his handling of national security issues.

A new Rasmussen Reports national telephone survey of Likely Voters shows 37% give the president good or excellent ratings on his handling of national security issues. Slightly more voters (40%) say the president is doing a poor job when it comes to national security. (To see survey question wording, click here).

Last week, just after his decision to get involved in Libya, 43% gave the president positive marks for his handling of national security, while 34% rated his performance as poor.

Positive marks for the president on national security are now at their lowest level since he took office in January 2009. His poor rating is the highest measured since last August. One year ago, 45% gave the president positive ratings on national security, while 32% rated the job he was doing as poor.

The really bad news?  The survey asked voters to rate Obama on two issues — national security and the economy — and he did best on national security.  On the economy, his approval rating is 34/66, while he gets a barely-better 37/62 on national security.

Let’s take a quick look at the internals.  The only demos Obama wins on the economy are black voters (88/11), Democrats (just 65%m with 35% disapproving), self-described liberals (77/22) and those unsure of their ideology (56/45), and those earning under $20K (57/44).  He wins the same demos for national security, but adds only 40-49YOs (50/49).

Who does that leave out?  Notably, independents are deeply dissatisfied on both issues, rating Obama 21/78 on the economy and 27/71 on national security.  Self-described moderates are also seriously disaffected, 36/63 on the economy and 41/58 on national security.  Women are just as unhappy on both issues, 34/64 on the economy and 40/59 on national security.

Young people, the enthusiastic base for Obama’s 2008 grassroots rise, are downright disillusioned, rating him 44/53 on the economy and a catastrophic 36/62 on national security.  It’s worth noting that only 8% of 18-29YOs rate Obama as “excellent” on national security, while 44% rate him as “poor.”  That’s the worst rating among all age demos; he only gets significantly worse ratings from Republicans (62%), self-described conservatives (54%), and people earning between $75-100K per year (57%).