When Congress convened back in February, it seemed the one tie that bound Republicans and Democrats was bipartisan desire to end the marriage tax. As the November election draws ever more near, that wholesome desire is being overcome by craven lust for political advantage.

Early in the session, the House overwhelmingly passed a $182 billion tax cut for married couples. The Senate, fast trading in its reputation as the more deliberate chamber for one as the place where nothing ever gets done, is splitsville.

Senate Democrats want to attach amendments on Medicare reform, prescription drugs and tuition tax credits. Republicans say it’s a blatant attempt to force them into unpopular votes. Democrats say it’s the only way they can get needed debate on these important issues around the GOP’s “procedural blockade.” Republicans say…

And even if Republicans succeed in shedding nongermane amendments and get something through, President Clinton says the package has become so laden with non-marriage tax breaks of Republican origin he may have to veto it. The question is no longer how to end the marriage tax, but how to stick the other party with the blame for not ending it.

There is, in fact, a marriage tax. Middle-income couples who make roughly the same incomes pay more than they would as singles. But there’s also a marriage bonus. The wider the difference between what the husband and wife earn, the more they save as joint filers.

It has to do with progressive tax rates and the fact that the standard deduction and personal exemptions for a couple are less than double what they are for singles. About 42 percent of joint filers in 1998 paid an average marriage penalty of $1,400, while 51 percent got an average bonus of $1,300.

It dates back to 1948, when Congress changed the tax code to try to reconcile the fact that millions of young husbands were returning from the service to rejoin the workforce with the fact that hundreds of thousands of young widows were trying to hold down jobs and raise children. It’s just became more of a problem as more married women entered the work force and as the gender gap in incomes narrowed.

The marriage tax is not deliberate, it is not part of a plot to destroy the family. But — in a country with a tax code bigger than the planet Earth phone book, with individual taxpayers winning and losing dozens of different ways every time they fill out a 1040 and with special interests constantly butting heads with budget caps — it is complicated.

What’s not complicated is the cause of the Senate’s irreconcilable differences. February, with its bipartisan billing and cooing, was then. This is now, and Election Day 2000 comes before Tax Day 2001.