Avoiding a Contradiction with an Adjective Caveat Clause

Yesterday, President Barack Obama gave a farewell address.

I was amused by his reference to terrorism,

"... Because of the extraordinary courage of our men and women in uniform, because of our intelligence officers and law enforcement and diplomats who support our troops --
no foreign terrorist organization has successfully planned and executed an attack on our homeland these past eight years.
And although Boston and Orlando and San Bernardino and Fort Hood remind us of how dangerous radicalization can be, our law enforcement agencies are more effective and vigilant than ever....."

It seems to say first that there were no terrorist attacks and then to list 4 of them.

However, Obama (image from the speech) used a few extra words. In the 'no terrorist attack' sentence, the first word that caveats the sentence is 'foreign'. Then in an adjective clause, 'successfully planned and executed', the 'no terrorist attack' sentence has a further caveat. Thus we have Obama claiming to have stopped attacks and also claiming credit for having law enforcement learning from attacks. 

Transcript of the speech is here.