On Tuesday, we weighed in on the idea that President Obama is failing to live up to a key promise of his presidency: competence.

We noted a Pew poll showing just 43 percent of people think Obama can get things done, while 51 percent think he can't. Those numbers are pretty striking. But wait, there's more.

If you dig a little deeper, you'll find that Obama's worst issues aren't ones on which the American people disagree with him; they're the ones on which Obama has failed to deliver on something on which most Americans agree with him.

Results, it seems, are as important as -- or more important than -- being on the right side of the issue.

A new poll from CNN and Opinion Research tested a dozen issues and asked how much people approve of the president on those issues. Obama's second- and third-lowest-approval issues? Immigration (35 percent approval) and gun control (33 percent).

On both of these issues, Obama's approval is worse than his approval rating even on health-care policy (36 percent) -- which is supposed to be his biggest demerit -- as well as the still-lagging economy and even the new Veterans Affairs Department scandal.

A new Washington Post-ABC News poll shows pretty much the same thing, with Obama's approval on immigration lagging behind his approval on the economy, health care and other issues (though his disapproval on immigration is lower).

As it happens, Obama's positions on both gun control and illegal immigration are actually quite popular. Polls show a strong majority of Americans support comprehensive immigration reform that includes a path to citizenship for illegal immigrants, and they also show around 90 percent of Americans back the idea of increased background checks for gun purchases -- a bill that failed in the Senate after the shootings in Newtown, Conn.

On both issues, the public is on the same page as Obama. So why in the world would these be among Obama's very worst issues? Because he hasn't delivered.

In each case, Obama has seen support from Democrats fall off as he has been unable to achieve his policy objectives. In fact, according to the CNN poll, 42 percent of Democrats disapprove of Obama on gun policy, along with 67 percent of independents. On immigration, 34 percent of Democrats and 67 percent of independents disapprove.

The president's approval ratings on these issues was never high, but in both cases, it trended upward as he tried to do something about them -- the push for new gun restrictions last year and his 2012 executive order halting deportations for young illegal immigrants -- only to fall to new lows today.

Few things could demonstrate better that, for a two-term president, being right isn't sufficient. You need to get results.