Asthepopulationsofthefreestatesgrowfarmorequicklythanthoseoftheslavestates，thenumberofNorthernRepresentativeswasboundtooutstripthatoftheSouthernveryrapidly。TherealseatofthepoliticalpoweroftheSouthisaccordinglytransferredmoreandmoretotheAmericanSenate，whereeverystate，whetheritspopulationisgreatorsmall，isrepresentedbytwoSenators。InordertoassertitsinfluenceintheSenateand，throughtheSenate，itshegemonyovertheUnitedStates，theSouththereforerequiredacontinualformationofnewslavestates。This，however，wasonlypossiblethroughconquestofforeignlands，asinthecaseofTexas，orthroughthetransformationoftheTerritoriesbelongingtotheUnitedStatesfirstintoslaveTerritoriesandlaterintoslavestates，asinthecaseofMissouri，Arkansas，etc。JohnCalhoun，whomtheslaveholdersadmireastheirstatesmanparexcellence，statedasearlyasFebruary19，1847，intheSenate，thattheSenatealoneplacedabalanceofpowerinthehandsoftheSouth，thatextensionoftheslaveterritorywasnecessarytopreservethisequilibriumbetweenSouthandNorthintheSenate，andthattheattemptsoftheSouthatthecreationofnewslavestatesbyforcewereaccordinglyjustified。
Finally，thenumberofactualslaveholdersintheSouthoftheUniondoesnotamounttomorethanthreehundredthousand，anarrowoligarchythatisconfrontedwithmanymillionsofso—calledpoorwhites，whosenumbershavebeenconstantlygrowingthroughconcentrationoflandedpropertyandwhoseconditionisonlytobecomparedwiththatoftheRomanplebeiansintheperiodofRome’sextremedecline。OnlybyacquisitionandtheprospectofacquisitionofnewTerritories，aswellasbyfilibusteringexpeditions，isitpossibletosquaretheinterestsofthesepoorwhiteswiththoseoftheslaveholders，togivetheirrestlessthirstforactionaharmlessdirectionandtotamethemwiththeprospectofonedaybecomingslaveholdersthemselves。
Astrictconfinementofslaverywithinitsoldterrain，therefore，wasboundaccordingtoeconomiclawtoleadtoitsgradualeffacement，inthepoliticalspheretoannihilatethehegemonythattheslavestatesexercisedthroughtheSenate，andfinallytoexposetheslaveholdingoligarchywithinitsownstatestothreateningperilsfromthepoorwhites。InaccordancewiththeprinciplethatanyfurtherextensionofslaveTerritorieswastobeprohibitedbylaw，theRepublicansthereforeattackedtheruleoftheslaveholdersatitsroot。TheRepublicanelectionvictorywasaccordinglyboundtoleadtoopenstrugglebetweenNorthandSouth。Andthiselectionvictory，asalreadymentioned，wasitselfconditionedbythesplitintheDemocraticcamp。
TheKansasstrugglehadalreadycausedasplitbetweentheslaveholders’
partyandtheDemocratsoftheNorthalliedtoit。Withthepresidentialelectionof1860，thesamestrifenowbrokeoutagaininamoregeneralform。TheDemocratsoftheNorth，withDouglasastheircandidate，madetheintroductionofslaveryintoTerritoriesdependentonthewillofthemajorityofthesettlers。Theslaveholders’party，withBreckinridgeastheircandidate，maintainedthattheConstitutionoftheUnitedStates，astheSupremeCourthadalsodeclared，broughtslaverylegallyinitstrain;inandofitselfslaverywasalreadylegalinallTerritoriesandrequirednospecialnaturalisation。Whilst，therefore，theRepublicansprohibitedanyextensionofslaveTerritories，theSouthernpartylaidclaimtoallTerritoriesoftherepublicaslegallywarranteddomains。