Barack Obama’s  policy shift on Cuba shows a more determined leader who is working through his promised agenda before his term ends. Photograph: Pete Souza/Reuters

US president Barack Obama’s decision to radically shift US policy toward Cuba is the latest and most striking example of a president unleashed from th(...)

 An official walks past a hazardous materials response team truck outside a mail sorting facility in Hyattsville, Maryland. An envelope addressed to US Senator Roger Wicker  tested positive for ricin at the facility where mail bound for the US Capitol is sorted. Photograph: Drew Angerer/Getty Images

The FBI arrested a Mississippi man yesterday in connection with letters sent to President Barack Obama and two other officials that are believe(...)