Nyora kupfuurira kweiyi ndima - Rosas akatarisana nekutyisidzira kwakawanda pasimba rake mukupera kwema1830 uye kutanga kwema1840. Akarwa muhondo
mukurwisana nePeru neBolivian Confederation, akatsungirira kuvharirwa neFrance, akatarisana nokupandukira mudunhu rake uye akarwa kupandukira kukuru kwakagara kwemakore uye kwakapararira kumapurovhinzi akati wandei eArgentina. Rosas akaramba achiwedzera simba rake mumapurovhinzi, achivadzora zvakananga uye zvisina kunanga. Pakazosvika 1848, akanga awedzera simba rake kupfuura miganhu yeBuenos Aires uye akanga ari mutongi weArgentina yose. Rosas akaedzawo kubatanidza nyika dzaiva pedyo dzeUruguay neParaguay. France neGreat Britain pamwe chete vakatsiva kurwisa kweArgentina, vachivharira Buenos Aires kwechikamu chikuru chekupera kwema1840, asi vakatadza kumisa Rosas, ane mukurumbira wakawedzerwa zvikuru nekubudirira kwake.