The real problem with the modern American Conservative movement is that it is flat out wrong. I can't think of a single "conservative" issue on which they can claim any evidence of the strength of their position. They've never balanced a budget using "conservative principals". They've never produced long term economic growth using them. They've never conducted a foreign policy that anyone would want to emulate.
Conservatives would have avoided both WWI and II. They hated Nixon going to China. Then they turned around and wanted a stronger policy in Vietnam. They hated detente.
They oppose abortion, they advocate celibacy, they try to legislate morality all the while complaining about the "nanny state".
They want to cut taxes, increase spending, undermine the middle class, and off shore production. NONE of that has "grown the economy" at all and in fact has been shown to weaken us in both a military as well as economic sense. Even their most recent attempt at an "austerity" movement has been shown to be based upon flawed data and to be exactly the opposite of what they propose.
They can't point to a single long term success of anything they espouse, and that includes their attitudes towards environmental "conservation".
They've failed, repeatedly.
And contrast and compare that with liberals. Liberals can claim huge long term successes, everything from Social Security to the union movement. They were right about civil rights, and continue to be right as we move forward with LGBT rights. They're right about the environment. They've managed to balance budgets, and reduce deficits. They've won wars. And the democrats anyway have always been larger than the republicans, and in fact ran congress for 40 straight years, something the GOP has NEVER done.