pls paraphrase antithesis and synthesis in the quote

A larger context for understanding the part in bold
What does the bolded part mean?

Clintonism Continued. Another possibility is that the conservative era [yields not to its liberal antithesis, but to a Third Way synthesis.] This would mean picking up where Mr Clinton left off in terms of fiscal responsibility, governmental reform and global engagement. In such an era, the momentum would come not from an energised left but from a vital centre. Neo-Clintonism would seek out compromise with moderate Republicans to put the federal fiscal house in order while pursuing healthcare and other reforms in an incremental rather than a sweeping way.