If John McCain were truly a maverick, he would publicly break from the politically correct culture that demands obedience to its global warming narrative. But sadly, he continues to do the opposite.

Liberals have denominated McCain a maverick because he has taken so many positions contradictory to his party's platform and to the conservative ideology that undergirds it. Now that he is the putative Republican nominee, you don't hear much about his maverick nature, but it's certainly not because he's changed his ways in opposing his party.

Last week, he affirmed his commitment to comprehensive immigration reform, even though earlier he stepped back from it to curry favor with conservatives. One wonders what other shoes will inevitably drop should he win the presidency, especially because he has indicated he would most likely be a one-termer.

Will he revert to his visceral revulsion to the Bush supply-side tax cuts? Many supply-siders, after taking McCain to the woodshed on the issue, assure us he can be trusted on it.

If so, their efforts will redound to the benefit of the economy and nation should McCain win the election. But some of these same supply-side advocates insist we shouldn't expect him to move rightward on too many other issues.

Sorry, but I reject that zero-sum thinking, as should my fellow supply-siders; they certainly do in the realm of tax policy. While I will vote for McCain against either Democratic opponent, I don't believe we should abandon efforts to reform the "reformer" on other issues besides taxes. Are we supposed to declare a moratorium on the expression of our principles for fear it could damage his electability?

If conservatives don't make an effort to hold McCain accountable for his liberal proclivities, then no one will, to the guaranteed detriment of the national interest. In fact, pushing him to the right while we still have a chance will enhance his electability.

Which brings me back to the subject that inspired this column: McCain's regrettable upcoming speech outlining his vision to combat global warming.

In a preview of the speech, CNN reports that McCain will say: "We stand warned by serious and credible scientists across the world that time is short and the dangers are great. The most relevant question now is whether our own government is equal to the challenge."

No, Sen. McCain, the most relevant question is whether political leaders will have the diligence to study this issue and the integrity and courage to stand up to the propaganda of the enviro-bullies. The question is whether you can be a maverick where it counts. Continued...