1 letter:
.

2 letters:
go, ic, ir, kr, mi, po, ss, tt

3 letters:
bow, cia, eln, eta, far, fcs, fig, ftc, gao, gpo, iaa, inc, jra, ngo, nih, npa, nra, nsc, nsf, plo, ruf, sba, ssa, tax

4 letters:
alir, bite, bond, cisc, coup, csis, dojc, drms, duty, egtk, exec, fema, fund, gaol, giro, gspc, huge, huji, irak, iraq, jail, land, ltte, mint, mrta, nara, nasa, nist, nrlb, ntis, osha, part, plot, rein, rule, sirc, till, tone, usss

5 letters:
build, china, clamp, clink, elect, exile, float, floor, grapo, index, iraqi, issue, mayor, money, organ, power, quash, reach, reins, relax, state

6 letters:
action, agency, ahpcrc, attack, augean, bounty, bureau, censor, change, colony, consul, county, course, digest, exocet, expose, figure, freeze, hobbes, kashag, keynes, la paz, nation, nester, office, papacy, policy, polity, putsch, quango, rebela, resort, reveal, syrian, taiwan, tangle, tariff, taxman, tigers, trough, vizier, wheels

7 letters:
al-iraq, anarchy, cabinet, capital, capitol, country, deplore, de jure, diarchy, dyarchy, effendi, embargo, fascism, federal, fifthly, impress, kremlin, loyally, madrasa, mandate, mintage, misrule, oppress, peter i, premium, red sun, restive, revenue, service, shelter, slammer, soviets, subsidy, taleban, taliban, treason, tyranny, unitary, utility, warlord, warship

8 letters:
al-jihad, business, congress, conjoint, conspire, denounce, discrete, division, dragoman, federate, friedman, friendly, glasnost, governed, governor, jeremiad, mandarin, minister, ministry, national, pentagon, politics, populate, powerful, pressure, pretoria, republic, revenuer, royalism, sedition, sol rojo, squatter, takeover, taxation, totalism, townsend, treasury, unformed

9 letters:
allegiant, authority, blue book, caesarism, cape town, city hall, communize, cost-plus, democracy, despotism, direction, exchequer, exciseman, executive, favorable, federally, federated, fire code, franchise, hold-down, homestead, home rule, implicate, insurgent, jailhouse, jobcentre, judiciary, manifesto, monarchal, monarchic, monocracy, municipal, ombudsman, operative, ordinance, portfolio, president, puka inti, quasi-ngo, rationing, recapture, red cloud, reformist, secretary, seditious, self-rule, shogunate, socialist, soil bank, stalinism, superfund, theocracy, town hall, truculent, uncle sam, war power, whitehall, work camp

10 letters:
absolutism, al-ma'unah, arrogation, autocratic, bondholder, bond issue, centralize, collective, commission, courthouse, crossbench, democratic, devolution, dissidence, federalise, federalist, federalize, fiat money, food stamp, free press, free trade, great seal, insurgence, insurgency, judicatory, judicature, legitimate, lions club, mauritania, mauritanie, micronesia, militarism, minimalist, muritaniya, ochlocracy, oppressive, powerfully, preemption, proclaimed, prosecutor, provincial, radicalism, rebellinga, rebellious, republican, resistance, responsive, revolution, ruthlessly, sapiential, secularist, settlement, shire town, socialised, socialized, statehouse, state bank, subvention, subversion, subversive, tax income, treasuries, tyrannical, unmilitary, war vessel, washington, white book

11 letters:
air marshal, alexander i, broad arrow, bureaucracy, chancellery, civil order, combat ship, constituent, corrections, countercoup, county seat, county town, coup d'etat, customhouse, death squad, destabilize, devolvement, dislocation, expropriate, giro cheque, green paper, health code, homesteader, human right, impressment, interahamwe, kalon tripa, khmer rouge, land office, land reform, last minute, lawlessness, license fee, license tax, machiavelli, master plan, ministerial, monarchical, nationalist, nonviolence, officialdom, officialese, organic law, outspokenly, paper money, paternalism, peace corps, politically, pontificate, post office, pre-emption, price floor, prison camp, prison farm, progressive, provisional, recognition, rent-rebate, res publica, seigniorage, sky marshal, socialistic, sovereignty, sumptuously, suppressive, syndicalism, tax revenue, teapot dome, technocracy, territorial, underground, unorganized, us congress, white house, white paper, withholding

12 letters:
announcement, backgrounder, back channel, body politic, central bank, city manager, commissioner, commonwealth, confiscation, constitution, county agent, crossbencher, customshouse, czar peter i, dictatorship, disaffection, domestically, enlightening, forcefulness, governmental, grant-in-aid, heavy-handed, high treason, home reserve, indian agent, interpellate, in any event, kaplan group, keynesianism, laffer curve, lese majesty, liberalistic, local option, mercantilism, municipality, nonviolently, one-man rule, pacification, policy maker, premium bond, price-fixing, prix de rome, propagandist, public works, pupet regime, puppet ruler, puppet state, savings bond, secret agent, sick benefit, spokesperson, tamil tigers, totalitarian, town meeting, trade policy, unresponsive

13 letters:
administrator, building code, bureaucratism, civil service, collateralize, confrontation, derequisition, double dipper, event planner, federal court, federal party, fiscal policy, folding money, head of state, individualism, islamic jihad, laissez faire, licensing fee, misgovernment, national bank, national debt, national park, parliamentary, patent office, persona grata, playing field, price control, price support, progressivism, protest march, puppet leader, receptiveness, reform-minded, republicanism, revenue stamp, royal society, sanitary code, second empire, squandermania, tax collector, thomas hobbes, trade embargo, trust busting, u.s. congress, united states, us government, washingtonian, welfare state, works program

14 letters:
asbat al-ansar, chief of state, civil marriage, classification, double dipping, downing street, federal agency, federal office, foreign office, french academy, governmentally, inland revenue, interpellation, labor contract, military issue, municipal bond, national guard, paper currency, pork-barreling, pronunciamento, public servant, public service, public utility, reorganization, representative, russian agency, salafist group, secret service, sipah-e-sahaba, special branch, trade stoppage, undersecretary, us post office, war department, ways and means

15 letters:
agency security, alien absconder, british cabinet, caliphate state, chief executive, commission plan, communist party, destabilisation, destabilization, economic policy, elder statesman, enfranchisement, episcopalianism, extension agent, federal deficit, fifth amendment, fire department, fundamental law, hearing officer, instrumentality, judicial branch, judicial review, judicial system, kitchen cabinet, labor agreement, local authority, managed economy, milton friedman, navy department, ordnance survey, peter the great, plenipotentiary, public property, public treasury, self-government, state-supported, state socialism, state treasurer, totalitarianism, u.s. government, withholding tax

16 letters:
authoritarianism, bond certificate, capitol building, czar alexander i, declassification, executive agency, executive branch, federalist party, federal district, federal tax lien, foreign minister, government agent, government issue, hearing examiner, internal revenue, local department, local government, machiavellianism, price-controlled, republican guard, republic of iraq, security service, sickness benefit, social insurance, state capitalism, state department, state government

17 letters:
band of partisans, congregationalism, constitutionalism, constitutionalist, counterinsurgency, county courthouse, government agency, government income, government office, japanese red army, mercantile system, military governor, nationalist china, national monument, new people's army, persona non grata, police department, political science, public prosecutor, puppet government, republic of china, spanish civil war, superfund program, us secret service

18 letters:
administrative law, agricultural agent, farm credit system, federal department, federal government, government revenue, independent agency, intelligence agent, legislative branch, passive resistance, population control, russian revolution, secretary of state, self-determination, sovereign immunity

19 letters:
aleksandr pavlovich, comptroller general, cultural revolution, diplomatic building, diplomatic minister, direct-grant school, february revolution, former armed forces, freedom of assembly, government-in-exile, government building, government minister, government security, interagency support, invasion of privacy, john maynard keynes, military commission, niccolo machiavelli, political scientist, prosecuting officer, revenue enhancement, subversive activity, teapot dome scandal

20 letters:
collective agreement, executive department, fourteenth amendment, government officials, informer's privilege, intelligence analyst, intelligence officer, islamic army of aden, libyan islamic group, municipal government, prosecuting attorney, treasury obligations, world tamil movement

21 letters:
government department, libyan fighting group, nonviolent resistance, vanguards of conquest

22 letters:
egyptian islamic jihad, intelligence community, internal revenue agent, lautaro youth movement, united states congress

23 letters:
aden-abyan islamic army, capital of south africa, iraqi national congress, national trading policy, united states president, world tamil association

24 letters:
correctional institution, federal trade commission, francis everett townsend, harkat-ul-jihad-e-islami, mortgage-backed security, national liberation army, united states government

25 letters:
american federalist party, articles of confederation, department of corrections, harakat ul-jihad-i-islami, interdepartmental support, national security council, state-sponsored terrorism, united states post office

26 letters:
government printing office, islamic army of aden-abyan, national rifle association, public-service corporation, revolutionary united front

27 letters:
central intelligence agency, democratic-republican party, secret intelligence service, tupac katari guerrilla army

28 letters:
communist party of kampuchea, department of justice canada, financial management service, government accounting office, lautaro popular rebel forces, nationaol science foundation, nongovernmental organization, united states secret service

29 letters:
collector of internal revenue, libyan islamic fighting group, national institutes of health, party of democratic kampuchea, small business administration, us government printing office

30 letters:
department of local government, federated states of micronesia, islamic republic of mauritania, national labor relations board, president of the united states, social security administration

31 letters:
great seal of the united states, military intelligence section 5, military intelligence section 6, national intelligence community

32 letters:
department of commerce and labor, liberation tigers of tamil eelam

33 letters:
army for the liberation of rwanda, executive office of the president, palestine liberation organization

34 letters:
salafast group for call and combat, tupac amaru revolutionary movement

35 letters:
federal emergency management agency

36 letters:
department of the federal government, patent and trademark office database, united states intelligence community

37 letters:
great proletarian cultural revolution, movimiento revolucionario tupac anaru

38 letters:
anti-imperialist international brigade, canadian security intelligence service, national technical information service, security intelligence review committee

40 letters:
al-jama'a al-islamiyyah al-muqatilah bi-libya, army high performance computing research center, association of islamic groups and communities, criminal intelligence services of canada, defense reutilization and marketing service, department of health education and welfare, first of october antifascist resistance group, international association of lions clubs, lautaro faction of the united popular action movement, national aeronautics and space administration, national archives and records administration, national institute of standards and technology, occupational safety and health administration, united states government accounting office, united states government printing office