With respect to lawmakers, why did Gov. Jerry Brown state that "Republicans appear to have no power"?

What will be an ideal response?

Varies. The Republicans' votes are not needed to pass bills, because the Democrats hold a strong majority in both houses (in fact Democrats attained supermajority status in 2012 and 2016), and members generally vote along party lines. Republicans' votes aren't needed to pass the budget either, because as of 2010, only a simple majority is required. When Gov. Brown made this statement, the Democrats held a supermajority in both houses and the Republicans' votes weren't needed to raise taxes or fees, which require a two-thirds vote.