DAYS before he seeks re-election to Congress for an eighth time, Representative Mike Capuano of Massachusetts has yet to order a single bumper sticker or “I Like Mike” lawn sign. That is not as risky as it might sound. In his district, a Democratic bastion that covers the Massachusetts Institute of Technology, chunks of Harvard University and swathes of blue-collar Boston, Mr Capuano faces no Republican opponent—or opposition of any kind. His is the only name that will appear on the ballot on November 4th.

This is no novelty for Mr Capuano. After he first won the seat in 1998, he never faced a Republican opponent again, often cruising to victory with such Cuban-style scores as 99.6% of the vote. Pondering past races, he struggles to recall details of the few independents who have challenged him. “I had a Communist, right?” he asks an aide. “A Socialist? Six years ago? Four?”

Few others in Congress have been as safe for as long. But Mr Capuano has more company than before. Ever-fewer races for the House of Representatives are closely fought, leaving four-fifths of that body’s 435 members with little to fear on polling day. Their doomed challengers—formerly stirred to action by a mix of idealism, ambition, vanity and (at times) self-delusion—seem at last to be noticing the odds against them. Add on the soaring costs of any election, and a growing number are quitting the field.

In 2014 Republicans have put up no challenger in 37 House races, while Democrats are ceding 32 districts without a fight, according to David Wasserman of the Cook Political Report. A further eight House districts will see no contest between the main parties, thanks to a “top two” primary system used in Washington state and California, in which ordinary voters (rather than just party members) can pick the two candidates who compete for each seat in the general election—a move sold as a cure-all for partisan extremism, but which can turn safe districts into blue-on-blue and red-on-red fights. That total of 77 single-party House races is high by recent standards and marks a big jump since 2012, when there were 45 of them. Stephen Colbert, a comedian, once persuaded a Florida congressman running unopposed to tell the camera that he liked cocaine and prostitutes, by arguing that it didn’t matter what he said because he couldn’t possibly lose.

One-party districts cannot be good for democracy. In Massachusetts this year Republicans are running in only three of nine House races and are contesting half the seats in the state legislature. Mr Capuano, a plain-speaking former mayor, says that having a Republican opponent would have “virtually no impact” on him. In such a safe seat, danger comes from his own side. His elections are fought months before polling day, he explains. Any Democratic challengers have a narrow window to show themselves by making exploratory calls, collecting signatures, turning up to public events, and generally testing whether the congressman is vulnerable. Mr Capuano aims to be “very conscientious” about constituency service at all times, but between January and April in election years, “I step on the gas.” All signs of possible weakness are watched for. Whenever he runs unopposed in his Democratic primary he counts the blank votes cast, precinct by precinct, knowing that rivals are doing the same.

In today’s Democratic Party, challengers seldom invoke ideology, Mr Capuano notes, contrasting his lot with that of Republican incumbents who must fear organised attacks from the right. In politics, Republicans are like dogs, working as a pack, he suggests: “Democrats are the cats.” The congressman, 62, has something of the tom-cat about him: it is possible to imagine him ruling a maze of alleys, with many scars and a torn ear. Asked about fund-raising (he has $628,000 cash on hand, according to his most recent electoral filing), he growls: “I do my share.” Almost all will be given to other Democrats, he explains, though he will keep enough money “to dissuade potential opponents”.

An old alley-cat might call Curt Myers an idealistic pup. A 21-year old Republican college student from Brookline, just outside Mr Capuano’s fief, he has chosen to mount a hopeless bid for the Massachusetts state House, running in his home district of 15th Norfolk, a hotbed of liberalism which last saw a Republican candidate before he was born. He is realistic about his chances, but wants to give his home town “the debate it deserves”. He has beaten his fund-raising target of $25,000—enough to build a website and buy some yard signs. He is heartened that the Democratic incumbent has agreed to a public debate and that even “far-left” folk say they are glad that he is running—though they will not vote for him. Less hearteningly, he has been spat on three times for being a Republican. Alas for fans of democratic accountability, Mr Myers does not think he would run for Congress against similarly bleak odds.

Showing up is 80% of life

In part, this is a story about the professionalisation of politics. Even unwinnable House races are now monitored by cold-eyed number-crunchers. Both parties fear zealous amateurs who may pollute their national brand. They also fret about the effect that one race may have on another. For example, in Massachusetts Republicans have a good chance of winning the governorship so long as turnout is not too high (because conservatives are more likely to vote). So a strong Republican challenge in a close House race might be counter-productive, spurring Democrats to pour in resources, raising turnout and kneecapping the chances of the Republican in the more important race.

Why stop at 77 seats with no inter-party contest, then? “It’s going to get worse before it gets better,” predicts a Republican bigwig. Such political vacuums surely cannot last indefinitely: voters would not tolerate a House with hundreds of uncontested seats, touch wood. Until then, the creaking of a two-party system in distress will grow louder.