For example, the Senate's proposal to raise the age of eligibility and its version of means-testing for the elderly were in neither the House bill nor the recent budget agreement between Congress and the president.
Mr Duncan Smith is understood to have initially resisted the latest proposal, arguing money should be found by means-testing benefits such as free bus passes and winter fuel payments for better-off pensioners.
Mr Duncan Smith is understood to have initially resisted the welfare cuts proposal, arguing savings should be found by means-testing benefits such as free bus passes and winter fuel payments for better-off pensioners.