Gary McCullough, director of Christian Newswire, has called Democratic presidential candidate Sen. Barack Obama’s attack on Focus on the Family president James Dobson a “political blunder” that could have a significant impact on Evangelical swing voters who were otherwise lukewarm towards Obama’s opponent, Sen. John McCain.

Sen. McCain’s past ambivalence towards same-sex marriage and embryonic stem cell research, McCullough wrote, had not excited the hard core of evangelicals.

“The evangelical community had been fairly unimpressed by John McCain.  But Obama has shown a grave lack of political wisdom: he did not let this sleeping dog lie,” McCullough said in an opinion piece published on Christian Newswire.

Dr. James Dobson’s June 24 radio show critiqued Obama’s use of Scripture in justifying his political policies and positions. The next day Obama responded to the evangelical leader’s critique by saying that Dobson was “making stuff up,” which McCullough said was “an indirect way of calling Dobson a liar.”

McCullough said Obama’s treatment of Dobson eliminated any sympathy Obama would have received for the attacks on his religious associations, such as his long relationship with Rev. Jeremiah Wright. Obama’s remarks also would be perceived as an insult towards “the single, most powerful influence on evangelicals,” he claimed.

Dr. James Dobson’s radio show reaches about 1.7 million listeners.

“His mistake could prove to make the difference in November -- in favor of McCain,” McCullough wrote.

Speaking to CNA, McCullough said that Obama’s remarks concerning Dobson shows he gets into trouble when he is “off-script and not reading from a cue card.”

“He picked a fight that he can’t unpick,” McCullough suggested.