Charlie Cook’s National Journal post “While Republicans Rant About Benghazi and IRS, Public Mostly Yawns” puts GOP meme-mongering about the two ‘scandals’ in adult perspective:

… At this point, the significance of each is more in the eye of the beholder. Liberals and Democrats tend to de-emphasize both affairs, while many conservatives and Republicans think that each rises to the level of impeachment. It will take time to know which end of this ridiculously broad spectrum of assessments proves to be more accurate.
…One wonders whether the same Republicans who are frothing over Benghazi would have been quite as vigilant had they been in Congress after the bombing of the Marine barracks in Beirut in October 1983, which killed 220 U.S. Marines, 18 sailors, and three Army soldiers in the largest single-day loss of American military since Vietnam and the largest number of Marine Corps fatalities since the Battle of Iwo Jima. By the end of December 1983, hearings and investigations were complete, reports had been issued, and the tragic episode soon became history (other than to the families and friends of those lost). In today’s political culture, such sad events have considerably longer shelf lives.
…Perhaps the best way to determine whether either (or both) of these stories is starting to resonate with the American people is to simply watch Obama’s daily and weekly Gallup job-approval ratings. After all, this is the first presidency that will be covered from start to finish with daily public-opinion samplings. Since the beginning of March, the president’s approval ratings each week have been between 47 and 51 percent, and between 48 and 50 percent for all but two weeks. For the week of May 6-12, with the last interviewing being conducted Sunday night, Obama’s approval rating was at 49 percent, down a point from the previous week, and his disapproval was at 44 percent, the same as the week before.
According to the Gallup Organization, the average job-approval rating for presidents in their 18th quarter in office, covering the post-World War II period, was 51.3 percent. That’s a little over a point higher than where Obama is right now. Bill Clinton had the highest job-approval rating at this point in his presidency over the past 50 years, with 57 percent. Ronald Reagan was at 55 percent, George W. Bush at 46 percent, and Richard Nixon at 45 percent. Nixon had been above 50 percent until early April, and then he began his gradual decline, never to recover.
If Obama were a stock, you could say he has a very narrow trading range; indeed, one can argue that he has had a higher floor and lower ceiling in terms of job approval than any other modern president. His bedrock support–particularly among minorities, youth, and liberals–keeps him from dropping below a certain level in all but the worst weeks. But the equally vehement opposition among conservatives and older white men puts a ceiling on how high Obama can go in even a great week.

Going forward, Cook suggests,

The most objective way to ascertain whether either or both of these stories have “legs” and are beginning to get traction with the public is to watch every Monday afternoon for the release of the Gallup approval rating for the previous week, ending the night before. Although you can look at the Gallup three-day moving average, those have a smaller sample size than the full week of interviewing and tend to be somewhat volatile. As long as Obama’s job approval remains in that 47-to-51-percent range, particularly between 48 and 50 percent, it’s safe to say that neither story is hurting him significantly, at least with the public. If you are going to look at other polls, take a gander at that poll’s “trading range” for Obama over March and April, and see whether it drops below that range. Each pollster’s methodology is a bit different, and each has its own idiosyncrasies, making comparisons between polls a little more iffy. It’s always better to compare each poll with previous numbers from that specific pollster.

Cook adds that such distractions tend to burden second-term presidencies by taking away time and attention from more urgent problems. He could have also added that these distractions also help Republicans avoid acknowledging that the budget deficit they have been whining about for years as the mother-of-all-issues is now rapidly declining.