Story highlights Democrats plan to hammer Donald Trump on national security during the general election

The foreign policy focus won't be limited to the presidential race

(CNN) The harsh words from President Barack Obama and Hillary Clinton toward Donald Trump this week -- in which the two Democratic leaders said Trump is unfit to serve as commander in chief -- preview a broader general election strategy from the presumptive Democratic nominee.

"Foreign policy is the playing field on which Hillary Clinton is making the argument that Donald Trump is disqualified," a top Clinton aide told CNN. The focus on national security was the plan even before the terror attack in Orlando, as Clinton's first major speech of the general election was a national security take-down of Trump.

Foreign policy may be a staple of Clinton's wheelhouse, but it is new presidential campaign terrain for the Democratic Party, which has traditionally been more comfortable fighting on domestic turf. In 2004, the first presidential election after 9/11, George W. Bush and his allies aggressively painted Vietnam veteran John Kerry as weak on national security, even calling into question his war record with the infamous series of "swift boat" ads. The argument was so effective that when Osama bin Laden released a video just days before the election, it further sealed Kerry's defeat.

But this year, top Democrats believe the party has a leg up on foreign policy and a chance to mirror the strategy that helped fuel Democrats' takeover Congress in 2006.

"People were so concerned with President Bush and policies that they viewed as reckless, and not particularly thoughtful, that they opened the door to Democrats on national security," said New York Democratic Rep. Steve Israel, who believes the same thing is happening now. "People view Donald Trump as reckless, antagonistic and uninformed, and they are opening the door to Democrats."

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