You can write three or four scenarios for how the Democratic race will go; you can write 60 for the Republicans. But there are a couple of things to keep in mind as Republicans decide. One is that it seems increasingly possible that no candidate will emerge from the primaries and caucuses with a majority of delegates. That uncertainty means the nominee may not be determined until late spring. Such tardiness could help Democrats in a year when voters already say they'd prefer a Democratic president to a Republican.
Second, the preference for smaller rather than larger government is not as ample as it used to be. The strongest case against big government has been its failures in the 1970s, typified by gas lines and stagflation. But the median-age voter in 2008 was born around 1964, so he or she never sat in those gas lines or struggled to pay rising bills with a paycheck eroded by inflation. That demographic factor helps explain why Democrats today are promising big-government programs, unlike Bill Clinton in 1992, when the median-age voter remembered the 1970s very well.
America has enjoyed low-inflation economic growth for 95 percent of the 2008 median-age voter's adult life. This is a record unique in history, which neither party is addressing particularly well. Democrats promise tax increases on at least some high earners (by not extending the Bush tax cuts past 2010), though tax increases are not the usual prescription for an economy that may be headed toward recession.
Republicans, facing an electorate half of which doesn't remember the 1970s and most of which has not appreciated the generally good economy we've had since 2001, have yet to muster persuasive arguments for their policies.