Ted Cruz is surging.  He's taken the lead in Iowa, according to multiple polls.  He has tied Trump in South Carolina in one poll, and in another poll he is only four points behind nationally (although he still lags nationally in other polls).  But if Cruz wins Iowa and South Carolina, he is extremely likely to win the nomination, if past history holds.

So what can Trump do to win?  He can try to increase his base of support, but the best move might be to try to take Cruz down.  That's what Trump did when he attacked Jeb! for being low energy, that's what he did when he joked about Ben Carson stabbing people, and that's what he did with Scott Walker, Marco Rubio, Lindsey Graham, Rand Paul, and a few others.

But attacking Ted Cruz could be trickier.  There are several lines of attack, none of them obviously beneficial:

1) To attack his qualifications to be president, as some in the tinfoil hat crowd do.  But Trump himself has said that Cruz is qualified, so that probably won't work.

2) To attack Cruz from the left.  Trump tried that when he attacked Cruz for not supporting ethanol subsidies, but Cruz was immediately defended by conservative talk radio, and the attack was seen to backfire on Trump.

3) To attack Cruz's personality.  Trump tried this a bit by saying that Cruz was a "bit of a maniac" in the Senate, which was perceived as a statement of support for Cruz's nemesis, Mitch McConnell.  That also backfired on Trump.  In general, it is hard to find grounds to criticize Cruz's personality.  He is even-tempered, high-energy, and more consistent on the issues than any other candidate.

4) To attack Cruz from the right.  This is hard to do but not impossible.  Rubio has tried it by claiming that when Cruz, in an effort to weaken Rubio's amnesty bill, supported an amendment to legalize illegals but deny them citizenship, Cruz was actually showing his support for illegal aliens.  But not just conservative talk radio, but Jeff Sessions and Mike Lee and other senators who were there came to Cruz's defense, noting he was trying to scuttle the whole amnesty bill.

There are grounds to attack Cruz from the right.  He did vote for the terrible procedure which allowed Obama's Iran deal to avoid a two-thirds vote of the Senate.  He did initially vote to give Obama fast trade authority before voting against it.  And he did previously support a vast expansion of H1-B visas (though he has since changed his tune on that).  And of course, while he supports building  a wall on the border and enforcing immigration law, he has not called for the kinds of mass deportations that Trump has.

So there is a way to attack Cruz from the right, if done carefully.  But carefully is not Trump's strong suit.  He is more likely to attack the way Cruz parts his hair or goes to the bathroom than his support for H1-B visas.  But I think, given the way that Cruz is surging, Trump will have to do something to counter him or risk getting left behind.

This article was written by Ed Straker, senior writer of NewsMachete.com, the conservative news site.