President Obama's poll numbers plunged over the last month, as the White House faced a backlash over several controversies, including revelations about the National Security Agency's phone and online data-mining programs. A CNN/ORC International survey released Monday found that Obama's approval rating had dropped by eight percentage points to 45 percent, his lowest in 18 months.

The poll marked a first for Obama — one he won't relish — with half of respondents saying they didn't believe he was honest and trustworthy. Americans were split on the controversial NSA program that tracks phone logs, although they supported the agency's targeting of internet traffic linked to foreign terrorism suspects overseas.

The news was not all bad for the White House, but it gave the administration plenty of good reasons to be concerned about Obama's ability to pursue his agenda early in his second term. Here are three particularly troubling signs for Obama:

1. Obama's base is wavering

"The biggest concern for Obama and the Democrats," says Joe Gandelman at The Moderate Voice, "should be news that he has quickly lost a chunk of two pillars of his traditional support": Voters under age 30, and independents. "And this can't be good news for the Democrats heading into the mid-term elections," says Gandelman. "It also means Obama is likely to have an even harder time in Congress with the Republicans, who'll look at this and conclude that Obama is now politically on the ropes."

2. The trust problem could grow

"With a majority not finding the president trustworthy," says Rick Moran at American Thinker, "and the ObamaCare rollout making everyone antsy, expect the president's approval to continue to slide over the next few months." More than six in 10 Americans now believe the U.S. government is so big and powerful that it threatens our liberty. That does not bode well for the person at the top of that government. "It will be a summer of discontent in America with the target of people's angst being the president," says Moran.

3. GOP attacks are starting to stick

"Scandal Mania" appears to be what has torpedoed Obama's approval rating, notes Taylor Marsh at her blog. Not all of the Republican criticism of Obama and his administration is valid, of course, but now that the attacks are gaining traction that is not really what counts. "When there are cumulative news events that raise question about trust, it hardly matters that the Benghazi terrorist attack onslaught has been proven incorrect on the facts, or that the White House had nothing to do with the IRS snooping on conservatives groups."

Obama's brand has been damaged by a contagion of news stories, not all fair but still having a cumulative effect, depicting a president who seems unrecognizable to many Americans compared to the person who came into office in 2008. [Taylor Marsh]