MEGAN MCARDLE: Clinton Support Has Nowhere To Go But Down.

By allowing Clinton to take the lion’s share of the fundraising dollars and the media attention, the party has left itself without a plausible alternative candidate. That seemed dandy as long as she was easily trouncing Republicans in polls. But those polls were always going to narrow, because the early polls were basically measuring whether people recognized the candidate’s name, not whether they were going to vote for her more than a year hence. As the GOP race sorts out, and the front-runners achieve more public awareness, you’re going to see our highly partisan electorate lock into much narrower margins.

Moreover, Clinton will have less room to improve her margins than whoever the Republican is. The Clintons have been around for a long time, which is a help in many ways — great name recognition, a beloved politician who can campaign for her, the ability to promise that the boom times under her husband will come back if only we give her our vote. But it also means that the public’s ideas about Clinton are pretty well fixed. A scandal can drive them down, but they are not going to suddenly soar as the public finds her surprisingly more likable than they expected.

When Democratic voters and pundits start to suspect that this race is not, in fact, going to be the easy walk they were expecting, they will probably start to look harder at alternatives. Realistically, so far what they’ve got is … Martin O’Malley, whose signature achievement as governor was hashing his state’s Obamacare exchange so thoroughly that it had to be scrapped and replaced — along with his hand-chosen successor, who lost to a Republican in a very blue state.

So, more competent than Hillary, then.