The political Left has been known to orchestrate frame-up attacks designed to make it appear that right-leaning opponents are responsible for violent acts and plots.
If I wrote the paragraph above in the context of reporting or commenting on the pipe bombs that were reportedly sent by an unidentified person or persons to prominent Democrats, many people would react angrily, and rightly so. After all, there is no evidence that the atrocious but thankfully unsuccessful targeting of the Obamas, the Clintons, CNN, George Soros, and Eric Holder (as well as Debbie Wasserman Shultz, whose Florida office was given as the return address on some of the packages) was carried out by political leftists. There is no proof that any Democrat was hoping to cast suspicion on Republican supporters, to suggest to voters, less than two weeks before the midterms, that Trump and GOP rhetoric incites violence. To intimate, in the absence of any proof, that left-wing agitators may be responsible would be a condemnable smear.