Assemblywoman Cristina Garcia (D-Bell Gardens) is working on climate legislation. For most of the debate in Sacramento over extending California&rsquo;s cap-and-trade program, the goal has been reaching a two-thirds vote in both houses of the Legislature to get the job done.That&rsquo;s the target set by Gov. Jerry Brown and the threshold that nonpartisan legislative analysts believe would insulate the program from legal challenges.However, there&rsquo;s&nbsp;increasing interest among some key lawmakers in&nbsp;requiring only a majority vote.&nbsp;That would lower the political hurdles to reaching an agreement but leave one of the state&rsquo;s most important efforts on climate change vulnerable to lawsuits.The issue was raised again this week by Assemblywoman Cristina Garcia (D-Bell Gardens), one of the lawmakers working on the issue. A recent state appeals court decision suggests &ldquo;we only need 41 votes [in the 80-member Assembly] to continue with cap and trade,&rdquo; she said during a Wednesday committee hearing.It&rsquo;s a controversial stance shared by Assembly Speaker Anthony Rendon (D-Paramount) but one that concerns&nbsp;Senate leader Kevin de Le&oacute;n (D-Los Angeles). The debate over how many votes are needed is a reminder that the future of cap and trade, which requires companies to buy permits to release greenhouse gas emissions, is closely tied to California&rsquo;s intricate rules on taxes.Gov. Jerry Brown wants a two-thirds vote to extend cap and trade, and he wants it next month. The program wasn't launched with the two-thirds legislative vote required by Proposition 13 to raise new revenue, and business groups have spent years accusing the state of enacting an unconstitutional tax.A state appeals court rejected that argument last month. Supporters hope the decision may be broad enough to protect cap and trade from future lawsuits stemming from Proposition 26, a more recent ballot initiative that further tightened tax rules.An appeal is pending before the California Supreme Court, and some environmental advocates fear years of litigation that could harm the state's efforts to reduce greenhouse gas emissions."Legal uncertainty can act as a real barrier if it&rsquo;s not resolved," said&nbsp;Alex Jackson, a San Francisco-based lawyer for the Natural Resources Defense Council.Figuring out the next move is a balancing act. Although&nbsp;it&rsquo;s widely acknowledged that getting a two-thirds vote would be better for cap and trade&rsquo;s future, it's&nbsp;more difficult coming so soon after a tight vote to raise gas taxes for road repairs.That deal was reached only after Brown and legislative leaders cut side deals&nbsp;to win over key lawmakers with nearly $1 billion&nbsp;in funding for projects in their districts.Deciding whether to push for a two-thirds vote is &ldquo;going to be a risk-reward calculation,&rdquo; according to a source with knowledge of the deliberations.