Top three reasons Donald Trump is surging in the polls right now

Donald Trump 's surge in the polls isn't just the result of the usual bump presidential candidates historically enjoy after they sew up the primary battles and earn the "presumptive nominee" title. And it's also not just the result of Hillary Clinton 's mistakes, even though she is making some serious campaign errors right now. What has been happening over the last few weeks is that Trump has changed his attack and messaging in a subtle but effective way, so subtle that many pundits may have missed it. But here are the three things Trump is doing very well right now: 

A month ago, Trump was still talking and tweeting too much about the Republican opponents he had long since vanquished. But in the past week to 10 days, he's been much more focused on Clinton and that's had the dual effect of weakening her and persuading more and more reluctant Republicans to jump aboard the Trump train. But saying Trump is going after Clinton doesn't tell half the story; it's how he's attacking her that really matters.

First off, he's given her a new moniker that's sticking for a lot of the public: "Crooked Hillary." Trump no longer mentions Clinton on social media without that "Crooked" prefix. This was the same tactic that worked when he nailed Ted Cruz with the "Lyin' Ted" nickname and Jeb Bush with "Low Energy Jeb." A big part of successful campaigning involves quick and snappy sloganeering, and these nicknames have that in spades.

Secondly, Trump is hitting Clinton on a carefully se-lected array of issues that at one point or another will appeal to persuadable voters f-rom all persuasions. For hard core gun rights voters, especially in the South, Trump has been calling Clinton an outright "gun grabber." For mainstream conservatives who focus on foreign policy, he's been reminding everyone of the mess in Syria and Libya that began during Clinton's term as Secretary of State.

For moderate-to-conservative women who aren't so sure Clinton deserves the women's vote just because she's a woman, Trump has continued to allude to her alleged complicity in Bill Clinton's sexual misconduct cases and for what Trump says is her relative silence about violent discrimination against women in the Muslim world.

And for progressive voters, Trump keeps reminding everyone of Clinton's ties to Wall Street and other alleged financial deals, thus the "Crooked" in "Crooked Hillary." These attacks seem to be leaving more of a mark on the Democratic frontrunner than they're helping Trump. In both the NBC News/Wall Street Journal and ABC News/Washington Post polls, Clinton's numbers are more down over the last month than Trump's numbers are up. That's the thing about effective negative campaigning, it doesn't boost your support that much, it just erodes your opponent's support more. But that's usually good enough to win.