The Democrats are not exactly champions of Separation of Church and State but anyone who considers this to be an important issue should not even consider voting Republican. As weak as Democrats can be on the topic it is ingrained in the GOP platform. Don't take my word for it read the platform and you'll find that not only is the Republic platform an affront to one of our nations most basic principles it is also chock full of ridiculous crap.
There are two sections that are especially telling. "We The People: A Restoration of Constitutional Government" and "Renewing American Values to Build Healthy Families, Great Schools and Safe Neighborhoods" are both loaded with examples of the GOP's incessant need to insert religion into politics. In the former the subsections "Defending Marriage Against An Activist Judiciary", "A Sacred Contract: Defense of Marriage", "The First Amendment: The Foresight of Our Founders to Protect Religious Freedom", and "The Sanctity and Dignity of Human Life" are all clearly motivated by faith. If it were simply a matter of personal motivation and action there would be no problem. Unfortunately, this is the parties blueprint for how they intend to govern. Their views on religion have been and will continue to drive their public policies. They seek to enforce their personal take on faith on the rest of us. It is a bit ironic since they start this whole section with, "We salute Republican Members of the House of Representatives for enshrining in the Rules of the House the requirement that every bill must cite the provision of the Constitution which permits its introduction." The constitution not only does not "permit" injecting religion into government the only passages that mention it restrict its use.
The second major section I referenced above is no better. The level of deceit and hypocrisy is astounding. They make a few feeble attempts at claiming their motivation comes from sources other than religion. There are no studies and no scientific basis for these religious based claims. It is also interesting to note that the GOP frequently tries to portray itself as a champion of freedom and personal responsibility. How those two are compatible with legislating a rather restrictive dictatorial code of conduct routed in ancient folklore on everyone is beyond me. Insisting on such a high level of religiosity does not seem to improve their own ethics. So if you consider Separation of Church and State an important part of our democracy please think twice before casting a ballot for any Republican candidates. It is not just the national party that has such a terrible platform. Virtually every state platform abides by the national one. Maine's is slightly watered down and is poorly written. It reads more like talking points than anything else. Yet, it does manage to touch on all the same points and rams faith into many of the platforms planks.