The different branches of government have clearly defined roles, such as Congress to pass laws and raise taxes, or the president to conduct foreign relations
The extract is 'original material', so written for these revision notes, which implies it will be balanced and researched and written by politics teachers in the UK with no obvious political agenda in mind
Gun owners have entrenched rights in the US through the Second Amendment, while the UK perhaps offers greater protection to certain groups, e.g. paid parental leave
Congressional investigation creates a powerful incentive for the executive to ensure that its actions stand up to the potential glare of media attention