Well, there’s a remote island that belongs to Alaska that’s about two miles away from a remote island that belongs to Russia. You can swim across that.

en.wikipedia.org/wiki/Diomede_Islands

I mean, I’m sure that Russia can get forces across that. They’ve got a military base on their little island, and we’ve got a small Native American village on our little island.

But then you’ve planted some number of forces on a strategically-irrelevant island in the Pacific. You’ve blown your largest advantage, surprise, and you’ve dumped however many people there, with a supply line that dictates that you need to support them by having ships sail up, while you just kicked off a war with a country with a much larger navy and air force.

And it’s not much of a springboard to a beachhead that you can use for land-based logistics, because there’s no infrastructure up there.

en.wikipedia.org/wiki/Bering_Strait_crossing

The Russian side of the strait, in particular, is severely lacking in infrastructure. No railways exist for over 2,800 kilometers (1,700 mi) in any direction from the strait.[24]

The nearest major connecting highway is the M56 Kolyma Highway, which is currently unpaved and around 2,000 kilometers (1,200 mi) from the strait.[25] However, by 2042, the Anadyr Highway is expected to be completed connecting Ola and Anadyr, which is only about 600 kilometers (370 mi) from the strait.[26]

On the U.S. side, an estimated 1,200 kilometers (750 mi) of highways or railroads would have to be built around Norton Sound, through a pass along the Unalakleet River, and along the Yukon River to connect to Manley Hot Springs Road – in other words, a route similar to that of the Iditarod Trail Race. A project to connect Nome, 100 miles (160 km) from the strait, to the rest of Alaska by a paved highway (part of Alaska Route 2) has been proposed by the Alaskan state government, although the very high cost ($2.3 to $2.7 billion, about $5 million per mile, or $3 million per kilometer) has so far prevented construction.[27]

In 2016, the Alaskan road network was extended westwards by 50 miles (80 km) to Tanana, 460 miles (740 km) from the strait, by building a fairly simple road. The Alaska Department of Transportation & Public Facilities project was supported by local indigenous groups such as the Tanana Tribal Council.[28]

I think you forget that we have 24 hour satellite surveillance all over the globe.

If you think Russia could send a large fraction of its blue water navy to one single point on the globe while also mustering all those troops and equipment on the ground in Russia beforehand without the US knowing about it weeks before hand, you don’t have a good grasp on the level of technology employed in today’s military.

Also its alaska. Russia would be operating out of what, vladivastok maybe to take similarly shitty US ports in alaska.

If russia wants shitty coastal wilderness at uninhabitable climates they already have them.