Between the loose cannon Donald Trump and the ultraconservative Ted Cruz, Republicans have been doing their best to give the presidential election away. But it's worse than that: They are doing their best to drive voters into the Democratic fold for years to come.
With their targeting of Muslims, hostility to immigration reform, rejection of climate-change science and opposition to same-sex marriage, the two threaten to sharply narrow the party's slice of the electorate.
The question is: Will the Democrats accept the favor? It's easy to overlook how they are putting their own political future in peril. Bernie Sanders is not likely to win the nomination, but his robust challenge to Hillary Clinton makes it plain that the Democratic Party has shifted leftward just as Republicans marched the opposite way.
Sanders, remember, is a self-styled democratic socialist who always ran as an independent because he considered the Democrats insufficiently progressive. At the outset, he was considered this year's Dennis Kucinich-a preachy gadfly with no chance of winning. Yet he has come out ahead in 17 state contests, including eight of the past nine. In the process, he has exposed major weaknesses in Hillary Clinton's appeal.
Bill Clinton recaptured the White House for the Democrats after three consecutive losses by candidates perceived as too liberal on big issues such as taxes, crime and Communism. Bill Clinton was a master of playing to the center, providing an attractive option to independents and "Reagan Democrats."
But Hillary Clinton is doing something very different, in an obvious effort to appease the Occupy Wall Street faction. Eight years ago, she strongly identified with her husband's record. This year, she has said the 1994 crime bill he signed was too harsh, rejected a Pacific trade agreement she had previously lauded and endorsed a $15 minimum wage enacted in New York. She has also tried to sound like populist firebrand Elizabeth Warren on banking issues.
Maybe she can veer back toward the middle if and when she gets the nomination. But motivating Sanders' supporters to get to the polls will be crucial, and that need will put strong pressure on Clinton to stay in the left lane.
So it looks as though there will be a gaping hole in the middle of the political spectrum, with centrist voters forced to choose between an increasingly liberal Democratic Party on the one hand and, on the other, Trump or Cruz-who are anathema even to relatively moderate Republicans, much less independents.