The Netherlands abolished the death penalty from criminal law in 1870 and introduced a life sentence in 1878.So what was the maximum penalty from 1871 to 1877? If you had been around back then and wanted to knock someone off, it seems like that would have been your opportunity.
Returning to modern times, it's also interesting that the political party whose think-tank director made the call to reinstate capital punishment so quickly disowned him. (Don't be misled by the fact that the party in question is the Liberal Party; here, "liberal" means, at least on economic issues, what we Americans would call "conservative.") Even though, judging from the remarks in the article, 40 to 50 percent of the public favors the death penalty, it's considered dangerous to a politician's career to support the death penalty. A few prominent politicians have bucked the trend, though, which makes Holland a mirror image of the U.S. on this subject--a few big-time American politicians have done well in spite of opposing capital punishment, but they're a small minority.
Last point: as the article points out, one of the EU's conditions for admitting new countries to membership, including Turkey, is that they abolish capital punishment. Thus, if the Dutch really did seriously consider reinstating the death penalty, the political fallout would be felt far beyond Holland's borders.