The terror attack on 9/11 was caused by a failure of U.S. intelligence.

America simply did not have effective assets on the ground in Afghanistan under President Clinton and then, for a short time, President Bush.

Thus al Qaeda was able to grow in ferocity as the Taliban assisted them and finally launch the atrocious assault that killed 3,000 people and shocked the world.

Six of the Muslim killers violated U.S. immigration law but 13 were here legally.

That was caused by lax immigration policy.

So Donald Trump said this about the al Qaeda attackers:

DONALD TRUMP: "I am extremely, extremely tough on illegal immigration.  I am extremity tough on people coming into this country.  I believe if I were running things I doubt those - I doubt those people would have been in the country."

Mr. Trump went on to say that he doesn't blame President Bush for 9/11, but he doesn't believe Mr. Bush kept us completely safe either.

Jeb Bush, the president's brother, took exception to that:

JEB BUSH (R), FMR. FLORIDA GOVERNOR: "My brother responded to a crisis and did it as you would hope a president would do.  He kept us safe and united the country.  There's no denying that.  The majority of Americans believe that.  I don't know why he keeps bringing it up.  He doesn't show he's a serious person as it relates to being commander-in-chief and the architect of a foreign policy."

Governor Bush is correct in saying his brother's administration acted quickly to prevent any followup attacks and did heavy damage to al Qaeda.  Those are facts.

But the tempest is not really important right now, as America faces a bunch of new threats that are not being adequately addressed by the Obama administration.

So while the Trump-Jeb Bush back and forth may be good copy, it really serves no purpose.

Something else I noticed over the weekend was this analysis of Hillary Clinton by Mitt Romney:

MITT ROMNEY, 2012 GOP PRESIDENTIAL NOMINEE: "Her mistaken perspective on foreign policy has led to the fact that, frankly, there's no place in the world that I can think of where American interests have been bettered by virtue of Hillary Clinton having served as secretary of state. ((EDIT)) That record of the secretary of state I think will become the focal point of the debates in 2016 when a Republican nominee goes after that record.

((EDIT))

JAKE TAPPER, CNN ANCHOR: "You would vote for Donald Trump over Hillary Clinton though?"

ROMNEY: "I would vote for the nominee of the Republican Party, and I don't believe that's going to be Donald Trump."

That might have been just a standard interview by Governor Romney, but I suspect there's something else in play.

It is entirely possible that no Republican contender will lock things up in the early primaries.

If that is the case, the GOP could turn to Mitt Romney.

The governor received more than 59 million votes last time around, he is well known, he has establishment support ... something to consider.

And that's the memo.