According to most polls, Donald Trump is leading the GOP presidential candidates for the Republican nomination. The problem for the GOP, and the benefit for the Democrats, is Trump is one of the easiest Republican candidates for the Democrats to beat.
According to the Wall Street Journal:
In the GOP race, Mr. Trump is essentially tied with Mr. Carson for the lead. Some 58% of those polled view him negatively, compared with the 25% who view him positively, presenting headwinds should Mr. Trump become the nominee. What’s more, the billionaire performs much worse against Mrs. Clinton and Mr. Biden in hypothetical head-to-head matchups than does Mrs. Fiorina or Messrs. Bush and Carson.
Below is the WSJ polling on the Republican candidates: