What are we talking about specifically? Most of the things that happened in the Obama administration were following a pattern that has been going on for some time. That he failed to put out the fire is completely true, but the fire has been burning for a while now.
There was a distinct shift in doctrine and execution of aspects vital to stability, security and reliability. The first factor is one of the most obvious, in which I mean I point to the neglect of the Korean Peninsula, the expansion of ISIS and its evolutions, the interactions with Iran, ignoring of Israel and of course the on going diplomatic problem which has become Turkey and greater Europe. I will reiterate that this is not leveled squarely on the Obama administration, but under that extended period territory gained all but vanished. They had many opportunities to improve these elements not on a prospect of globalism or "unity", but of national interests; they did not, as was their policy.
The next element is security, which is one that can only be discussed to varying lengths, but the lacking of secured borders, extensive screening and vetting of foreign nationals, and a failure to fight a dynamic threat at its core has escalated the odds (as we have seen with the increased issues of detection for electronic devices). It is sad to comment on, but vehicle ramming type attacks, knife attacks and similarly cheap, expedient, efficient means will continue to rise to. More notably, to address the issue of "nuclear terrorism" that is an extremely unlikely scenario, what is more likely is an improvised radiological device that contaminates an area after detonation because of its psychological, not physical, potential; all of this stems from an eroded environment lacking a focus on physical national security.
As a side note, the
real threat of radical Islam is the conversion of the non-native populace and conditioning them to their customs or forcing them to abide laws foreign to their land. This is considered by some to be an "extreme" statement, but it is one I believe to be accurate because the radical Islamic leaders have realized, as a relative whole no matter their particular leaning on Wahhabism, that they cannot alter the strategic level without doing so. Looking at Europe as my point of reference, with its absolute and continued collapse between this factor and a broken economy, I believe it safe to say the mainland might be regrettably lost for the foreseeable future.
But I digress, last is the tenant of reliability, which is to say politically and militarily, the United States lost immense footing. The readiness of the armed services dwindled, its numbers waned, its morale dipped and its prominence again faded. It was not made a priority in a time where the enemy is active and in many forms and faces. This is not to say it cannot be effective, but it is not to the standard expected of it. This was compounded by the insult to injury given where the military and related services were not backed, most infamously in the Benghazi scenario. That example has been beat to death, but it will stand as testament.
To transition to the current topics, the credible threat is not nationalism in any case, be it found in the United States, China, Russia, the United Kingdom and so on. Political ideology is not the greatest external threat to anyone and the abstract demon of capitalist society is, in fact, its saving grace. Since the end of the Second World War, the booming defense industry has continued to display technologies and developments that are on the level of science fiction... all while pinching every pretty penny it can from the pockets of taxpayers. It is just the nature of the beast; it wants to be fed. Conflict and war feed it, with those times in between when it is most hungry. However, without it, I believe we would be worse off. I also need mention that it is not even linked with nationalism in the United States, to which I can only assume you are meaning in majority.
How do I come to that conclusion? No one is under the illusion that these companies have any other objective other than to make money off of martial technology. There's not the honor and superiority of the warfighter in it, but the understanding that without their presence, the United States would be lacking some of its core military assets; air, space and cyber warfare advantages. This is not to ignore how well prepared and equipped the land or sea based elements are, but it is no secret that the future of conflict is moving smaller and larger at the same time. Realistically, the only issues I really have politically with the behemoth is that the government is
terrible at making deals and prioritizing
anything, especially with independent contractors or agencies, at all levels, local all the way up to federal.
The tension I mention is of a different brand and methodology, again which is why I cite it as more dangerous. The fact alone you turned to the prior references is why I use it. In this era you are seeing a portion of the American populace directly sympathize with the enemy, to the extent of supporting or defending them both in word and action. You have citizens of a country attempting to defend tenants of radical Islam, ignoring the aspects of Sharia Law alone, and welcoming fundamental elements of foreign indoctrination that make self-radicalization possible. But, this does not end there, in that you have anarchists, socialists and communists often working hand in hand with this threat spectrum, all the way down to the bystanders who tend to get in the way rather than pose any threat at all. That is what concerns me and how easy it is to carry out an act of terror because of it. With the current political and social environment, such an action would not go unnoticed and with excuse; it is dangerous waters and should put anyone involved, regardless of their political or ideological side, on edge.
A financial crisis I am not unfamiliar to, as I think all of us here are of the age to remember it and be affected by it, but it still is not nearly as concerning as a depreciation in safety and security. Not to say it is of negligible impact, but this entire lengthy ordeal was just to explain my point and rationale. It should not bear repeating, but all of this is my opinion, formulated through my experiences and personal understanding.