This is Obama’s doing, he squandered resources trying to attack his own political enemies instead of keeping his eye on the ball.
Indeed the last 2 near misses should have waken him up to this threat. Instead DHS still focuses its efforts on watching TEA paryers instead of the proven Islamic terrorist threat.
There were many failures of Bush and Congress after 9/11, but DHS was definitely one of the biggest. They are a massive agency with an ill-defined mission and the money spent on bloating them far beyond the size of the original agencies (border patrol might be the exception) into DHS would have been better saved or spent on existing agencies.