WASHINGTON — Candidate Scott Brown campaigned as the potential 41st GOP vote to halt President Obama’s health insurance overhaul. Now, after his first full year as a US senator, Brown is helping the president make the new law more palatable to its critics. Although Brown insists he still opposes the overall health care measure, his bipartisan plan embraced by the president is one of the most visible examples of Brown’s willingness to rebuff his Tea Party movement roots and work in the Senate as a compromiser. With a voting record similar to those of Susan M. Collins and Olympia J....