I have a fiction piece I am working on, which contains a Empire whose people are anologues of Russians. They're paranoid, defensive, and prefer to build walls and castles wherever they go for safety. The land in which they live is a series of mountain and river valleys which abut a circumpolar glacier. The lowest latitude of their empire reaches roughly to the 57th degree N. Most of the Land is Taiga, boreal forest, and tundra.
This is the product of two and a half years of meticulous design, redesign, and playtesting with fellow writers in my area. Given all the Factors below, and the people described, is this federal-feudal system a stable enough government to protect the common man and woman of the Enarya from threats both foreign and domestic?
TL;DR at the bottom if you don't want a history lesson.
In this land, the people holed themselves in high mountain passes behind labyrinthian systems of fortifications and holdfasts, eternally warring as they sought new high grounds to acquire for their own defenses. The rulers of the mountain fiefs were the Vojvodi, and the lowland river-dwelling rulers styled themselves as Boyarin. They Traded food from the (relatively) prosperous rivers in exchange for metal and stonework found mostly in the mountains.
The Boyars, through mostly peaceful means, united the lowland towns and cities under their banners, and left the Vojvodi to themselves. They facilitated trade between the vojvodi, and their fellow boyars. After several centuries had passed, the Wars of the Vojvodi came to a standstill, as every conceivable fortifiable strategic point had been walled-off and defended many times over. Meanwhile, the Boyarin and lowland Enarya peoples had grown wealthier and more prosperous.
The Vojvodi, however, had grown gradually weaker and more desperate as their wars soured, and were faced with the possibility of their state being taken advantage of by the lowland boyars who resented the steep tariffs imposed upon their goods. As a compromise, the Vojvodi negotiated to join the Boyars, though with much greater autonomy than the mayors of their other constituencies.
After five centuries of consolidation and peaceful expansion, the greater area of Enarcha contained 6-8 Boyarin, and within each a massive quantity of vojvodi, provostyi (mayors), and the individual hetmans of the smaller villages.
This system was mostly peaceable and stable save for occasional skirmishes and minor disputes. It wasn't for another century thereafter when a foreign invasion took the southern coasts, displacing the Enarya en masse and nearly entering the valley itself. The Southern Boyarin formed hasty alliances and together fought the invaders to a standstill in the foothills of the vital passes. Being Enaryat, the alliance collectively contracted their vojvodi to create massive walls to span the length of the valleys, all while under constant pressure by increasingly desperate invaders.
The Bloody war was eventually ended when the Boyars finished their walls and manned the fortresses embedded along it. A final all-out assault by the invading force crumbled, resulting in a humiliating and decisive end to the incursion. Peace was signed, and the Boyarin reluctantly granted the Southern coast to the invaders, realizing that the land was simply indefensible past the mountains. Fearing future attacks by similar foes, the Western Coastal region was abandoned as well, its people quickly fleeing for the safety of the high walls of the mountains.
Sensing future conflict was inevitable, they reached out to the other Boyarin and gradually roped them into the alliance. The Northern Boyars acquiesced, with watchful eyes turned to the glacial tribes which had been encroaching steadily toward their borders. After much deliberation, the Boyars elected one of their own, Ivan Zakuviy, as the Tsar of Enarya, though they limited his authority with a strictly enforced constitutional system.
I have min-maxed as best I can for at least internal stability.
The Hetmans are pressured to help their neighbors and their families, and are indispensable to the Provostyi whom they serve. They are local tax collectors, fully knowledgeable about how much any given person can comfortably pay, and more than willing to accept goods instead of coin. They are not obligated to provide a coin amount for tax to the provost, but rather a fixed percentage. Thus, no greedy big-city taxmen causing poverty and famine in the villages. If any one Hetman steps out of line, there are several more nearby to condemn and divest him of his power by popular vote.
The Provost are accountable to their Hetmans, who, if they sense corruption or something amiss, will boycott elections and prevent the Provost's re-election to the post. The Provost does not collect his own town's coin for his living, but rather lives in housing provided by the Boyar he serves at no charge, and is paid a wage set by his Hetmans. He may only propose municipal laws, which must be confirmed or denied by popular vote with sufficiently high turnout.
The Vojvodi are paranoid and unwilling to leave their mountains for war, and defend their territory with single-minded determination. They have no interest in conquering the lowlands, nor the flat, windswept tundra beyond the borders. They are more than happy to be granted the borderlands, and guard them against foreign attack in exchange for exemption of their villages from taxation.
The Boyars are too busy dealing with the hordes of temperamental Provostyi to have designs on their neighbors, and leave the management of the peasantry to the Provostyi as long as the taxes keep rolling in. They maintain a retinue large enough to fend off a surprise attack, but usually are more than happy to let the Vojvodi spend outrageous sums of money and manpower on the defense of the greater realm.
Lastly, the Tsar has restricted authority, only able to settle negotiations between other Boyars. His authority is enforced by the non-contested boyars, and a large imperial retinue kept in the capital, which is paid for by the taxes of the Grand Provostyi (Mayors of the Great Cities who answer directly to the Tsar), as well as import duties and tribute from local protectorates. During times of war, he takes control of the Vojvodi, and organizes military responses to foreign aggression.
- Hetmans rule over villages less than 1,000. They organize elections and set the wages for their immediate superiors, as well as managing local tax collection.
- Provostyi rule over a single town of 1,000-5,000 and a number of local Hetmans. The total number of people must not exceed 15,000 between them. They propose laws, campaign for election, and have their wages set by their hetmans, and live in a home provided by their immediate superiors.
- Vojvodi are military marcher lords who man forts in the mountains in exchange for tax breaks. They answer to a boyar in peacetime, or the Tsar in times of war. They are paranoid about leaving their mountains, and don't want anything to do with the river-lands besides receiving food shipments.
- The Boyarin are middle-management for the realm, corralling and appeasing the Provostyi and the Local Vojvodi. They have the right to petition the Tsar, and have their concerns heard promptly. They also enforce the rule of the tsar against fellow Boyarin who step out of line.
- The Tsar directly controls the imperial military, and during wartime takes rule of the Vojvodi to organize defensive strategy. He directly rules the Grand Provostyi (who rule cities larger than 50,000 within the city proper). He gets their taxes, the import duties of international trades, and tribute from nearby rulers who bargain for protection. He is responsible for mediating the Boyars squabbles.
- There is historical reason for each to accept the system. The lowlands are mostly homogenous, while the mountains have some minor dialectical variation. The office of the Tsar has yet to fail to defend the nation, and the Boyars have grown wealthy and the land prosperous from the internal peace.
- The people are in all but the most extreme cases well-fed, represented by locally elected rulers, and only see the Boyars and Tsar when emergencies arise. Corruption exists, but mostly in petty bureaucracy within more scrutinized public offices.
- Since a commenter specifically requested this, assume rivers on the map located mid-post (designated by large, branching, riverine blue lines) are the more fertile land. The Southernmost areas have climates similar to the Caspian steppe, and thus their rivers form excellent land for wheat and barley, while the northernmost areas make do with pickling roots and tubers.