into a pool and charged higher premiums because of the various health care issues that we have. reporter: they say the aim is to lower costs by eliminating some taxes and creating more competition but even john boehner was skeptical of republicans ability to replace the law. they will fix obamacare. i shouldn t call it repeal and replace. that s not what is going to happen. they will fix the flaws. reporter: and pressure is mounting. republican lawmakers bombarded by angry constituents. many worried about dismantling obamacare. for people like brandy walker in arizona who has already had a double mastectomy, there are deep concerns about changing the law. i m still pretty young. i was 38. it would be difficult for me to afford. that was nbc s kristen welker with that report. joining us now, former democratic senator from montana,