Despite this, the Star Kingdom's political parties tend to be working alliances of individuals with the same basic interests rather than closed ideological systems even today. Party discipline is often impressive when close votes must be fought through, but there is no "collectivist discipline" in the sense that a member of a party must publicly endorse and support policies with which he disagrees simply because the rest of the party does. MPs are more likely than Peers to "vote the party line," but the tradition of "voting one's conscience" is the Manticoran ideal, and most of the Star Kingdom's political parties have their own distinct "left," "right," and "center" wings.

The more powerful parties are: the Centrist Party and its normal ally the Crown Loyalists; the Liberal Party; the Conservative Association; the Progressive Party; and the so-called "New Men" Party.

The Centrists, led by Allen Summervale, Duke of Cromarty, the current PM, are the largest single bloc, though they do not quite constitute a majority in their own right. The Centrists pursue a rather conservative domestic policy of gradualism and fiscal restraint, opposed to sweeping social changes and determined to avoid deficit spending. More importantly, they have been absolutely committed to the defense of Manticore against the growing Havenite threat for over fifty T-years, having believed that an eventual military confrontation was inevitable and should not be postponed in hopes it would go away. In particular, they believed that waiting for the Republic to weaken, however attractive it might seem, constituted a supine surrender of the initiative to their enemies and so invited long-term defeat. Moreover, unlike certain other political groups, the Centrists believe Manticore can survive open warfare with Haven and that even if they are defeated, the final cost will not be much worse than a craven surrender. It was the Centrists who supported Roger III in instigating the Star Kingdom's pre-war naval build-up and pushing through the annexation of the Basilisk System (a G5 star with a single habitable planet) to forestall Havenite occupation of the Junction terminus in that system, which was at the time a highly controversial move. Some critics saw it as the first step in a deliberate policy of imperial aggrandizement; others saw it as an unnecessary challenge to Haven which could provoke the very war they feared. The majority of Queen Elizabeth's subjects, however, supported the annexation, whatever their representatives might think. Of all the aristocratic-led parties, the Centrists have the strongest support in the Commons, which gives them an added depth that affords rather more clout than simple numbers might suggest.

The Crown Loyalists, led by Henry McShain, Marquis of New Dublin, might be thought of as Manticoran Tories. Their fundamental article of political faith is that stability and prosperity for all Manticorans depends upon the power and authority of the executive in the person of the monarch. From time to time, the Crown Loyalists differ with the current monarch on policy, but in those instances they generally seek to remonstrate in private while preserving a public front of solid support. The Crown Loyalists are extremely weak in the Commons. They are perceived, with a certain degree of justice, as the party of the great nobles, and while they are accorded great respect and deference, there is a belief (even among many Centrists) that they are insensitive to current issues, subjecting all of them to the litmus test of their effect on the Crown's authority (and the nobility's influence). Those who believe this also believe that the Loyalists will oppose any policy, however beneficial its final effects may be in other ways, if it weakens the Crown. In general, the Loyalists share the Centrist view on foreign policy, but they are even more conservative in fiscal policy (they felt pre-war taxation levels were excessive) and have always had difficulty resolving their contradictory support for a strong fleet and opposition to high military spending.

The Liberal Party, headed by Marisa Turner, Countess of New Kiev, advocates humanist reform and is relatively disinterested in foreign policy. They are larger than the Crown Loyalists but smaller than the Centrists and have less numerous but extremely loyal adherents in the Commons. Although disheartened by the current state of affairs in the People's Republic of Haven, the Liberals believe that the fundamental objectives of the Havenite Declaration of Economic Rights (see The Republic of Haven, below) were laudable. In their opinion, the pre-war Legislaturalist Havenite leaders were "bad liberals" who had become prisoners of the "mobocracy" of the Haven System. Their own concern is with "bringing the Star Kingdom into the main stream of modern galactic political thought" (ie., extending and enlarging the franchise, providing relief for the indigent, equalizing income, and promoting greater popular participation in government), and they do not pay much attention to the manner in which affairs beyond the borders may impinge upon Manticore. They regarded the Centrist Party's pre-war concern over Haven as alarmist, believing that however expansionist Haven's current leadership might be, it would hesitate to try conclusions with Manticore (lest it rouse the Solarian League by threatening the Manticore Wormhole Junction) and would eventually reach satiation and cease expanding. Since they preferred to increase spending on human services, they begrudged every penny spent on the fleet, which caused them to lose a great deal of public support once active hostilities with Haven broke out. Nonetheless, they continue to believe that "war never settles anything," and of all Manticoran political parties, they remain most comfortable with the official pre-war ideology of the People's Republic.

The Conservative Association, headed by Michael Janvier, Baron of High Ridge, is the smallest of the traditional political parties and might charitably be termed reactionary. It advocates an isolationist foreign policy, argues that foreign adventures are dangerous, and decries the "steady, liberalizing rot threatening Manticore with anarchy." As might be surmised, the Association is something of a crackpot group which attracts the nobles who find the Crown Loyalists entirely too permissive in defense of privilege. Indeed, they advocate return to an "original Manticoran balance of power" which never actually existed outside the imaginations of their own theorists. Although they felt the Centrists' annexation of Basilisk was an act of madness, the very sort of adventurism which could plunge Manticore into disastrous confrontation with foreign powers, Roger III and Cromarty knew they could be counted upon to support fleet appropriations, as their isolationist bent required a powerful fleet to police their borders.

The Progressive Party, headed jointly by the Earl of Gray Hill and Lady Elaine Descroix, is the third largest party and, in general, endorses many of the objectives of the Liberal Party. The Progressives share the Centrist determination to avoid deficit spending (which the Liberals see as an acceptable, temporary evil), would like to see "a better and more beneficial balance between social spending and military appropriations," and share the Liberals' distaste for foreign policy. Unlike the Liberals, they have never regarded concerns over Haven (which they see as an example of deficit-spending liberalism run berserk and corrupted by power-seeking politicos) as alarmist. On the other hand, they also felt (and, apparently, still feel) that any belief that Manticore can survive a fight to the finish with the Havenite military machine is lunacy. (Since the beginning of actual hostilities, the Progressives have been very vocally and publicly confident of Manticoran victory, but their opponents believe this is camouflage. According to this theory, the Progressive's present posture is designed to make their fear-based desire for a negotiated settlement appear to stem from their complete confidence in victory, instead.)