Star Trek: The Frontier Saga (2001-2005)
Set from 2378 to 2382, in the aftermath of the Dominion War. Often compared to DS9, as it continued themes of Federation fallibility and occasional amoral decision making. It followed a Starfleet vessel tasked with patrolling the Former Cardassian Union - early themes involved conflict with fellow victors of the Dominion War, the Romulans and Klingons. Later, they had to deal with a cell of Cardassian hyper-nationalists, and with an imperialistic Bajoran political movement, as well as the rising power of the Breen Confederacy. Along with that came conflict with remnants/successors of the Maquis, rogue Starfleet officers and individuals from the Federation traumatised by the events of the Dominion War, as well as the episodic problems that had little to do with wider galactic affairs.
Criticised for further diverging from Gene Roddenberry's utopian vision, it also drew ire from conservative commentators who had much to say about the series' portrayal of terrorists and war - an unintentional coincidence being that The Frontier Saga began broadcast only a month after the September 11th terrorist attacks, and the beginning of the War on Terror. Despite this - or perhaps because of it - The Frontier Saga enjoyed a loyal viewership. This declined after 2003, in which plotlines which appeared openly critical of the Iraq War led to a concerted effort to boycott the show. While this failed, the controversy led to a reversion to safer storylines which in turn disappointed viewers who had found the previous storyline engaging. Ratings declined and by 2005 the show faced cancellation.
The relatively poor performance, and controversial nature, of The Frontier Saga led to the first major hiatus in Star Trek on the screen (either big or small) since the end of the Animated Series in 1974. When Star Trek returned, it was in the form of a reboot, mirroring similar efforts to rejuvenate popular culture franchises, in 2009. These films took place in a different timeline following the adventures of the crew of the original Enterprise. This film was a box office hit, and while it drew criticism for rebooting the timeline, it did reignite interest in the franchise in a new generation.
The Frontier Saga underwent reassessment as the 'Kelvin Timeline' films came out - the series' attempts to tackle plotlines about terrorism and assymetric warfare now appeared prescient rather than controversial. It was for this reason that when a new Star Trek TV series came out - a collaboration between CBS and BlockbusterOnline - it was not set in the Kelvin Timeline but subsequent to the events of The Frontier Saga.
Star Trek: Odyssey (2017-present)
Picking up the thread from where The Frontier Saga left off, Odyssey brought Star Trek into the 'present day' ie keeping up with the pacing set by The Next Generation, that the events of Star Trek are always set 377 years from the date of broadcast. Odyssey was hence set in 2394, some twelve years after the events of The Frontier Saga. Initial ideas about a Kelvin Timeline TV series following Kirk's Enterprise on a traditional deep space mission were adapted into a new Enterprise under a wholly new crew, setting off from the Alpha Quadrant into the Delta Quadrant - effectively following up on what had happened there since the events of Voyager.
A feature of the show was a resurgent and bellicose Klingon Empire - the lowborn Martok was overthrown by hyper-traditionalists, who have severed the Khitomer Accords and slowly rebuilt their military might - in the years before the events of the show, a swathe of the Former Cardassian Union was occupied and illegally annexed by the Klingons and the embattled Cardassians are continuing to fight a clandestinely Klingon backed insurgency. Now, it is clear that the Klingons have prepared a grand armada to seek new conquests in the Delta Quadrant. Starfleet, fearing a coming battle with the Klingons, have sent the Enterprise to go ahead of any potential invasion and assess the status of the Delta Quadrant.
As well as Klingon warlords, the new Enterprise would face the fragmented remains of Borg Unimatrices, the vibrant but unstable Vidiian Sodality, a unified Kazon Order, and the mercantile federation of the Talaxian Hansa. Familiar faces from previous series would occasionally appear, such as disgraced former Ambassador and Klingon dissident, Worf of the House of Martok, and the telepathic energy life-form Kes.
The new series was immediately criticised online, even before broadcast, for a diverse cast that some believed was playing into politically correct narratives. Along with that were radical redesigns of traditional Starfleet uniforms, as well as of long-standing alien species - the Klingons being the most prominent and controversial. While the show explained their changes, by way of a supersoldier programme pursued by the new Klingon government, the new appearance did not sit well with a certain sector of viewers. Also controversial were narratives that paralleled political events - the Klingons had taken to their path of empire-building under a charismatic and populist leader who contrasted himself with a lowborn predecessor, which many alleged was a deliberate criticism of the Trump administration. Ongoing episodes portrayed a Klingon society that had become obsessed with purity to the detriment of honour and duty.
A more good faith criticism of the series narrative has been a tendency toward overarching plot arcs in the mould of other blockbuster TV series of the 2010s, such as Eragon. This tendency to follow complicated plots and a need to pursue twists, came at the detriment of the episodic nature previous Star Trek series had thrived upon. Odyssey's attempts to combine the two was unfavourably compared to Deep Space Nine's Dominion War plotline.
Despite these criticisms, Odyssey was considered a success and CBS soon came out with subsequent series held in parallel - Short Treks (appropriately these were short vignettes), Star Trek: Lowe Decks (loosely based upon the TNG episode of the same name, but set in 2394 aboard a different Starfleet vessel to the current Enterprise), and Star Trek: Worf (originally a series focussed around Picard was proposed but Patrick Stewart did not want to overshadow the new cast/crew of the Enterprise, and instead they turned to the established in-continuity character of Worf.)
Star Trek: Worf (2020-present)
Coming off the success of Michael Dorn's cameos in Odyssey, Star Trek: Worf was the first series of Star Trek (with the edge-example of Deep Space Nine) to follow a none-Starfleet crew, namely Worf's band of Klingon renegades. The former Ambassador is initially in a state of retirement/virtual house arrest on Qo'noS, but is arisen from his long melancholy first by clandestinely aiding the crew of the Enterprise-F. Following those events he becomes increasingly concerned about events regarding a secret renegade faction of the Tal Shiar which survived the supernova that destroyed Romulus and brought about the near-collapse of the Romulan Empire - and their seeming collaboration with elements of both the Federation and Klingon governments despite the supposed antipathy of all three.
Worf is torn by decisions he made when Ambassador, allowing his instinctive hatred of the Romulans to mean he turned his back on the refugee crisis. It did not take long for him to decide such an action was dishonourable and he has attempted to make amends. Quite what the status of the Romulan government is, remains something of a mystery this early on in the series - though it seems they are taking a rather worrying interest in the remnants of an abandoned Jem'Hadar fleet which was left behind in the Alpha Quadrant subsequent to the Dominion War.
As has been typical of Star Trek reboots and sequels, there have been criticisms of the altered aesthetics, from clothing to prosthetics. There has also been some narrative criticism, as Star Trek: Worf is the first series to fully commit to a serial rather than episodic structure. While most of the cast of regular characters consist of Worf's mostly Klingon crew, it is clear from promotional material that Worf will be joined by other newcomers such as a Vulcan martial artist, and other stalwarts of Star Trek notably Jeffrey Combs reprising his role as Weyoun (something of a mystery as yet as DS9 established that Weyoun 8 was the final clone after the cloning facility on Rondac III was destroyed in the Dominion War).
Great Powers of the Alpha & Beta Quadrants c. 2397
United Federation of Planets: A little bigger than it was fifteen years ago, but no less bruised. The final admittance of Bajor into the Federation has led to further fractious relations with the constitutionally neutral Cardassian Union - the Bajorans have disclaimed the illegal colonisation of Cardassian worlds by Bajoran Imperialist organisations, but it hasn't prevented incursions by them. Elsewhere, the Federation is struggling with the Romulan Protectorates, those worlds taken into the fold when the supernova of Romulus' star led to the near-collapse of the Romulan Empire. The poor management of the ensuing refugee crisis means many of this worlds resent Federation rule, and the steady re-emergence of a coherent Romulan state had led to calls for a restoration of the Neutral Zone. Starfleet's leadership has changed since Picard's day - they don't want to see the Federation reduced in any way - some kind of conflict with the Romulans seems likely.
Breen Confederacy: Always enigmatic, the Breen were the real winners of both the Dominion War and of the destruction of Romulus, in both cases taking dozens of worlds under their wing. They are now the second largest power in the quadrant - and are eyeing the rump Cardassian Union with glee, especially with the Klingon's incursions leaving the Cardassians' neutrality in tatters. One sore point for them was the accession of the Ferengi into the Federation - in the old days when latinum was the nagus, the Breen enjoyed a favourable relationship with the Ferengi. The last two decades have seen the Ferengi align themselves with the New Economics of the Federation, the alignment of the Ferengi Merchant Navy into Starfleet and finally full membership. With the Romulans on the rise, the Breen look more vulnerable than they have in decades, or at least they would if anyone had seen their faces.
Klingon Empire: The Romulan supernova eleven years ago brought about a seachange on Qo'noS. Chancellor Martok at first cooperated with Federation efforts to mitigate or prevent the supernova, despite his misgivings given tensions between the two Empires over the occupation of Cardassia. When these attempts failed, and the refugee crisis began however, he was outflanked by a reactionary group of Houses. He was challenged and deposed, and was disappointed as he witnessed Worf, embittered by the prospect of giving succour to the people who had killed his father, turn his back. The Klingon Empire has healed from the wounds of the Dominion War, annexed worlds from Cardassia as an ostensible protectorate, and has begun to sabre-rattle for further conquests in the still fairly unexplored frontier of the Delta Quadrant. The new Empire has essentially shredded the Khitomer Accords - the supposed reincarnation of Kahless disappeared years ago - and has taken a more prescriptive and exclusionary policy to non-Klingon subjects of the Empire. The traditional rights of clans and houses - particularly non-Klingon - has been curtailed to restore central power and authority to the High Council and in particular to the office of Chancellor. There are even allegations of ethnic cleansing, though the blockade on the exchange of information with the Federation means its hard to determine the truth of this.
Romulan 'Empire': The actual nature of the emergent Romulan state is difficult to ascertain. They use the old symbology of the Star Empire, though that may just be because of the longevity of the eagle in Romulan iconography since their ancestors left Vulcan. What is known is that they have taken an 'eggs in many baskets' approach, not wanting a repeat of the destruction of Romulus. They are intensely secretive, which again hardly differentiates them from the preceding Star Empire. But how the new empire is governed is not precisely known.