If it feels like you've been reading more and more stories about government-assisted terrorism plots—notwithstanding the one close to home that we're all talking about—that's because you really have been.

(Update, 11:30 am Sunday: If you're reading this because the Oregonian linked to it, thanks for visiting. Now be sure to stay awhile and read the rest of our coverage on Blogtown.)

Just in the past couple of months, sting arrests were announced in Washington, DC, and in Chicago. Last year, there were widely reported stings in Dallas and again in Illinois. As this story from last year in the Dallas Morning News explains, merely arresting people before they got going on plots themselves apparently wasn't paying off in convictions:

The undercover operation that led to the arrest Thursday of a 19-year-old Jordanian citizen—intent, according to authorities, on blowing up a Dallas skyscraper—may reflect a different approach by the FBI to terrorism investigations.

About two years ago, [law professor Jeffrey] Addicott said, "a decision was made that we're going to let these things develop a little bit longer so we can get the more serious offense. And we've seen the fruits of that."

What's also funny, not quite in a ha-ha way, is how familiar all the stories about these stings sound. It's actually spooky. Just check out these plug-and-play quotes from public officials.

Portland Police Chief Mike Reese, in a statement last night: "This threat was very real, but at no point was the public ever in danger."

Metro, the District of Columbia's mass-transit agency: "We want to assure our riders and employees that at no time was the public in danger during this investigation. The FBI was aware of Mr. Ahmed’s activities from before the alleged attempt began and closely monitored him until his arrest."

Chicago FBI Special Agent in Charge Robert Grant:
"At no time during the undercover operation was the public in danger, the entire event was controlled by FBI sources."

So if there was no danger—if the FBI was so integral to the process—then is there really a crime? Juries and judges tend to think so. In Dallas, the man caught in that 2009 sting, accused of plotting to blow up a skyscraper, was sentenced to 24 years in prison.

The paper in Springfield, Illinois, interviewed a defense lawyer about how successful invoking "entrapment" as a defense might really be. He wasn't too bullish.

Zealousness in agreeing to help with a terrorist plot can be sufficient for conviction. He said he knows of no instance in which an entrapment defense has proven successful in a terrorism case in which FBI agents or informants have posed as terrorists, and there have been dozens of such prosecutions.

Which means the sting is likely to stick around as an anti-terror "tool." And we have to wonder how else it might be used—and what other kinds of crimes government agents will be asked to encourage Americans to try to commit before arresting them.