All Muslim Lands are under the obligation to rule by Islam, through the Khilafah. Just like Salah, we do not have any other example to imitate, but that of the Prophet ﷺ. The Khulafaa Rashidun (ra) ruled by Islam according to his ﷺ methodology
Society is like gravity; It pulls us towards it, through our businesses, careers, spouses, children, neighborhoods and communities. We will fall, and fall hard, unless we pull ourselves up by the Rope of Allah ﷻ. Let our homes be modelled upon Dar ul Arqam, the incubator of the Companions (ra) of the Prophet ﷺ.
Regarding emergency response to the floods, the Khilafah would reject interest based loans, demand provisions from unaffected parts of the Muslim World, call upon Muslim troops to assist rather than US troops and focus fully on the disaster rather than be distracted by cheap power struggles.