To the surprise of most observers, Barack Obama pushed his announcement of his running-mate into the supposedly sancrosanct Olympics period, and may now push it into the Democratic Convention (the Olympics end Sunday, and the convention begins the next day). Apparently determined to "go second," John McCain may now be forced to unveil his running-mate relatively late as well.

Alexander Burns of The Politico has a nice summary today of the timing of recent veep announcements. Dan Quayle in 1988 was the last running-mate in either party to be announced during the convention itself.

As is reflected in a separate Politico article this morning which wanders all over the place in speculating about Obama's choice, his campaign has done a masterful job of maintaining suspense on the Veepship. A long list of potential candidates have taken turns as supposed front-runners, giving Team Obama a good sense of the likely reaction if any of them is actually chosen. In the end, no one really knows what Obama has decided on any of the key variables surrounding this decision: "outsider" versus "insider;" national security street cred versus fellow-war-opponent; "reinforcing" his message or complementing his weaknesses; newsgrabbing "controversial" choice or reassuring conventional choice. That's why a relatively large number of people are stiill considered possibillities.

There's less suspense on the Republican side, particularly after McCain emphasized the hard-line pro-life nature of his candidacy and future administration in the Rick Warren event over the weekend. Speculation increasingly revolves around Tim Pawlenty and Mitt Romney.