Yes, it is actually that easy. In fact this is exactly how Trump quickly eliminated the guy that at one point was thought to be his biggest rival, Jeb Bush. Admittedly, Jeb's campaign was not going so well and the fact that he often comes across as awkward and confused never helped him. Anyway, a couple of high school level swipes aimed at emasculating poor Jeb pretty much left him only able to get 7% of the vote in South Carolina and he suspended his campaign. Below is a section of Matt Taibbi's article (Dslacker provided a link to it in his post) that details this little debacle. It was a good strategy by Trump because he set his sights on eliminating Bush from the opposition first because he knew Bush could raise the most money and present him with the biggest challenge. By the time they hit South Carolina he had the Bush campaign on the ropes and delivered the knock-out punch described below.

---------------------------

In Greenville, Trump went after Jeb this time on the issue of his brother's invasion of Iraq.

"The war in Iraq was a big f ... fat mistake, all right?" he snorted. He nearly said, "A big fucking mistake." He added that the George W. Bush administration lied before the war about Iraq having WMDs and that we spent $2 trillion basically for nothing.

Days earlier, Trump had gleefully tweeted that Bush needed his "mommy" after Jeb appeared with Lady Barbara on a morning show.

Jeb now went straight into character as the Man Whose Good Name Had Been Insulted. He defended his family and took exception to Trump having the "gall" to go after his mother.

"I won the lottery when I was born 63 years ago and looked up and I saw my mom," Jeb said proudly and lifted his chin. America loves Moms. How could he not win this exchange? But he was walking into a lawn mower.

"My mom is the strongest woman I know," Jeb continued.

"She should be running," Trump snapped.

--------------------------------------

This probably left Trump wearing a giant grin because now he only had to compete with Cruz, who is absolutely despised by his own party, and Rubio, a guy that his own people call "the talking haircut" because he is so empty headed. I'm sure Trump thought if I only have to worry about those two morons I have this in the bag.

So, this stuff works and one stupid incident that portrays you in an unfavorable way that can be played again and again can cause a campaign to tank in a single news cycle.