The U.S. has for a long time been able to act militarily with no fear of a first-world opponent. That this will continue much longer is unlikely. Several years ago, a Chinese submarine surfaced inside a U.S. carrier battle group having been undetected. Russian anti-aircraft weapons are clearly formidable, and an apparent electronic warfare demonstration over a U.S. destroyer in the Black Sea caused consternation, though I’ve never read a report that provided any details on what actually happened then. Hypersonic Russian missiles make survival of even carriers debatable. The U.S. military industrial complex is formidable and may have tricks up its own sleeves but stealth isn't what it used to be and even if we have or can develop the ability to engage hypersonic anti-ship missiles and torpedoes the detection, identification, targeting, and destruction of incoming missiles will have to take place within a matter of seconds. As a troop or a crewman, I wouldn't like the sound of "margin of error" all that much.
Russia clearly has focused on the development of a defensive military capability and I think Putin himself has said that the next war will not be fought on Russian soil, suggesting to me not vast armored formations churning up the urine-soaked streets of Paris but thousands of missiles fired from Russian soil engaging logistics, command, communication, and troop targets deep inside Europe and ships at sea. Quantity has a quality all its own as someone has observed, and the U.S. has the decided advantage there, but I think we're looking at a Mexican standoff much more than U.S. "leaders" appreciate, especially as we are the ones operating at the end of an extended supply line. The Germans came close in both wars to shutting down supply shipping with their U-boats.
As in Aleppo, it [clearing out Idlib Governate] will mean unspeakable carnage, unless someone finally tells the insurgents theirs is a lost cause.As I’ve noted before, the 100-year anniversary of the First World War should be an occasion for mature reflection on the terrible destructive forces of modern warfare set in motion and fueled by people with too much pride and self-satisfaction and too little foresight. The West wounded itself terribly, if not mortally, by that hideous mistake and yet even now we have saber rattling and chest thumping by fools who don’t give a rat’s ass about facts or the will of the people but are motivated to kiss various unidentified asses and take money from mysterious benefactors.
That someone is you. The Israelis, Saudis, and others who want unrest to endure are egging on the insurgents, assuring them that you, Mr. President, will use US forces to protect the insurgents in Idlib, and perhaps also rain hell down on Damascus. We believe that your senior advisers are encouraging the insurgents to think in those terms, and that your most senior aides are taking credit for your recent policy shift from troop withdrawal from Syria to indefinite war.
Big Difference This Time
Russian missile-armed naval and air units are now deployed in unprecedented numbers to engage those tempted to interfere with Syrian and Russian forces trying to clean out the terrorists from Idlib. We assume you have been briefed on that — at least to some extent. More important, we know that your advisers tend to be dangerously dismissive of Russian capabilities and intentions.
We do not want you to be surprised when the Russians start firing their missiles. The prospect of direct Russian-U.S. hostilities in Syria is at an all-time high. We are not sure you realize that.
The situation is even more volatile because Kremlin leaders are not sure who is calling the shots in Washington. This is not the first time that President Putin has encountered such uncertainty (see brief Appendix below). This is, however, the first time that Russian forces have deployed in such numbers into the area, ready to do battle. The stakes are very high.
But it isn’t. An occasion for mature reflection. This U.S. is being destroyed internally by lunatic social and economic policies and yet again we see our political elite entertaining modern warfare without a thought to the day after. Bolton apparently cares more for his mustache than he does about the consequences of his posturing. God knows what Nikki Nookey cares about. Maybe taking on Kamala Gorilla and Pocahontas in the next wormfest to select our nextest president.
 "Ex-US Intel Officers Warn Trump Over Syria Attack: 'Don't Be Surprised When the Russians Start Firing Their Missiles.'" By Veteran Intelligence Professionals for Sanity. Russia Insider, 9/10/18 (emphasis added).