If the Russian ground forces remain as bad as they now appear; and if NATO can completely dominate the Baltic Sea, NATO might repel a Russian invasion of Estonia, Latvia, and Lithuania.
NATO is paying attention to defending NATO's eastern flank:
NATO countries are crafting new operational plans to defend the alliance’s eastern flank, where more than 150,000 ground troops are on heightened alert, the top U.S. military officer in Europe said Tuesday.
Gen. Christopher Cavoli, NATO supreme allied commander and head of U.S. European Command, said the region-specific plans are being devised to guarantee a rapid response to a crisis.
I see Russian threats to the NATO Baltic states of Estonia, Latvia, and Lithuania as the most serious. American defense and state department personnel last month met with Baltic state officials and "also participated in a tabletop exercise to explore policy options for a unified response in crisis situations."
While the readout didn't have specifics, I think the Russians have three options, not mutually exclusive. These scenarios are a Narva conquest based on the 1999 Kargil War between Pakistan and India (A), "little green men" "Russia world" coups (B), and a conventional invasion (C).
Little Green Men
Looking at the little green men scenario, preventing Russian airborne and naval infantry units from staging lightning grabs is good:
Estonian and German forces will train to defend critical infrastructure near the capital of Tallinn next month, a scenario in line with NATO’s new concept of strengthened forward defense, according to officials from both countries.
I think NATO could defeat this threat but it requires forces and plans to do so. As I wrote about the Crimea takeover in 2014, that success was based on unique factors that are unlikely to apply to the Baltic states. Local forces plus high quality NATO reinforcements will be sufficient to defeat this kind of invasion, lingering "hybrid war" hype notwithstanding.
Conventional Invasion
Russia could also invade overtly to directly conquer some or all of the Baltic states. The Russians can invade Estonia and Latvia from Russian territory while using fires from Kaliningrad to hit Lithuania and Poland.
With Belarus under Russia's effective control, Russia could more easily invade Lithuania, too.
I assume that Russia will have at least learned the lesson from its Winter War of 2022 that it must begin a war using massed artillery.
Baltic states naturally want NATO forces on the ground in strength to deter or defeat a Russian invasion.
But there is a danger of sucking NATO forces into Estonia and Latvia where they
might be destroyed by much larger numbers of Russian troops bulldozing
their way west. Or where they might be cut off by a main effort that focuses on advancing through Lithuania to link up with Kaliningrad.
NATO defense chiefs on Saturday discussed how to prepare Baltic member states to receive large numbers of troops from allied nations during a major crisis with Russia.
Again, I don't assume Russia's military won't get better--or be used better. I worry about NATO shoving its best troops too far north into a kill sack. Unless Belarus escapes Russian control, of course.
But at least NATO agrees that permanently stationing outside brigades in the Baltic states isn't the best idea.
I'm least worried about NATO troops going to Lithuania, the southernmost Baltic state. Because more troops there help NATO keep Kaliningrad isolated and hold open the possibility of taking it to clear up NATO's left flank; and hold territory for a counteroffensive north.
Still, adding Sweden and Finland to NATO makes dominance of the Baltic Sea more likely early in a war. Which would allow sea lines of supply to Estonia and Latvia rather than rely on a land line of supply through the Suwalki Gap on the Lithuania-Poland border.
Kargil 2.0
Finally, Russia could try to recreate Pakistan's Kargil strategy of 1999 by sending in "big green conventional units" to grab Narva, Estonia, dig in, and dare NATO to drive them out (quoting an earlier post):
Could Russia seek to use their relatively few quality troops on a narrow front rather than try their "little green men" astro-turf revolt tactic again that we will be more attuned to reacting to if applied to Estonia, a member of NATO, with its relatively large (a quarter of the population) ethnic Russian minority?
What if Russia attempts a page out of Pakistan's long territorial struggle against militarily superior India in the 1999 Kargil War?
What if Russia sends in their regular troops--while denying they are their troops--to seize the Estonian ethnic-Russian city of Narva on the northeast border and dares NATO to counter-attack, which would devastate NATO's reputation if we did nothing?
Russia could deny knowing who they are even as the Russians provide logistics and firepower support from Russian territory, using it as a sanctuary to to sustain the land grab in the hope that NATO's will to destroy a NATO city to save it falters.
NATO early reinforcements are useful for a Narva scenario where Russia tries Pakistan's strategy.
I suspect a Kargil 2.0 is the most likely option if Russia chooses to attack the Baltic states. Even Russia knows now that their military isn't good enough for a large operation. And Ukrainian partisan resistance in 2022 should finally end the hype of "little green men" so-called "hybrid" operations that sweep all resistance aside.
I'm hoping one of the tabletop exercises explored that kind of threat.
All that being said, Lord knows what option the Russians will think is possible after a few years of "solving" their military weaknesses.
UPDATE: The spirit is good:
U.S. Defense Secretary Lloyd Austin reaffirmed Washington's commitment to defend "every inch" of NATO territory ahead of a meeting in Brussels of defense ministers from the 30-member Western alliance on October 13 that will include closed-door discussions by its nuclear planning group.
But I do worry about that pledge in the case of the Baltic states. If "defend" means "repel" the pledge relies on Russia not fighting better than they have in Ukraine. "Defend" may need to mean "fall back, counter-attack, and liberate" every inch of NATO territory.
NOTE: War coverage continues here.