Politicians and political candidates duck questions they'd rather not answer. That's a bipartisan phenomenon. Sometimes conservative candidates duck questions. Is that good or bad? Well, it depends:
i) There's a difference between answers and explanations. It's often easy to give short answers, but it may be hard to give short explanations.
Controversial issues require lengthy explanations. It's not enough to give a quick, simple answer. You have to frame the answer. Take a step back and put the issue in context. Discuss what's wrong with the alternative.
Many voters don't even know that there are good arguments for conservative positions. They inhabit a partisan ghetto.
Liberal reporters and debate moderators like to pepper conservatives with controversial questions to make the conservative look bad. If a conservative candidate finds himself in a forum where he doesn't have time to defend his answer, it's best to duck the question than give a brief answer that will be used against him.
Conservatives need to take control of the situation. They have plenty of other opportunities to give detailed answers. They can issue a statement. Or sit down with a sympathetic interviewer. Or give a speech. Or make a video.
It's not incumbent on them to play into enemy hands by playing on enemy turf, playing by the rigged rules of the adversary. They should try to pick settings in which they can express themselves more fully. Choose their words more carefully.
ii) By the same token, conservative candidates are not obliged to address every controversial issue during the campaign. They can save some controversial issues for after the election.
Again, the liberal media baits conservative candidates into taking as many controversial stands as possible to bring their numbers down.
But it's okay for a conservative candidate to focus on a few major issues during the campaign, then revisit other issues if elected. You can reserve some things for later, when you're in a position to actually do something about it.
iii) Of course, what I said above only applies to bona fide conservatives. Sometimes, a candidate ducks a question because he's "moving to the middle". Dodging controversial issues can sometimes be symptomatic of a candidate whose ambition erodes commitment to conservative values. The higher he rises, the more "moderate" he becomes.