Rand Paul, a son of Texas Republican Rep. Ron Paul, is making official his 2010 campaign for a Senate seat in Kentucky.

Paul, an eye surgeon from Bowling Green, had referred to his Senate campaign as an "exploratory" effort. "Dr. Paul will now transition his exploratory committee to a full election committee," his campaign said in a release Wednesday.

Paul initiated his campaign in mid-May, when Republican Sen. Jim Bunning was still saying he planned to seek re-election. Paul is declaring his candidacy for Bunning's seat less than two weeks after Bunning said July 27 that he would not run.

In criticizing unnamed Republican leaders for doing "everything in their power to dry up my fundraising," Kentucky Sen. Jim Bunning didn't give a run-of-the-mill retirement announcement.

Political reporters are accustomed to members of Congress announcing their departure by saying that they've accomplished all of their goals in office or that they "want to spend more time with my family," even in cases when it's clear there are political factors influencing the decision.

But Bunning's goodbye on Monday was high and tight, just like the fastballs he used to throw as a Hall of Fame pitcher.

Kentucky Republican Jim Bunning's retirement announcement on Monday was the eighth by a senator whose seat is on a 2010 ballot. Barring a major surprise, that's probably the last Senate retirement that will be announced this election cycle.

The eight "open" Senate seats is above the average for the past few election cycles, more than the five in 2008 or the four in 2006 and matching the eight in 1994 and 2004. In the past three decades, only in the 1996 cycle were there more open Senate seats (13) than in 1994, 2004 or 2010.

Though the retirement announcement by Bunning, who was hampered by poor fundraising and approval ratings, probably increases the Republican Party's chances of holding his seat, open seats often are more difficult for the defending party to retain than those that incumbents are defending.

Back from another trip to the Senate's public records office, which is busy processing the dozens of campaign finance reports that senators and candidates had to mail by a July 15 deadline.

Most of the reports, which cover receipts and expenditures for the second quarter of 2009 and often run into the hundreds of pages, aren't yet available for viewing. (Unfortunately, the Senate doesn't mandate electronic filing of campaign finance reports). But here are some useful nuggets of information from campaign reports I did view earlier today.

Alabama: Talk about low overhead. Republican Sen. Richard C. Shelby, a shoo-in to win a fifth term in 2010, raised $1.4 million and spent just $96,000 doing so. That's less than 7 percent of his second-quarter receipts. Even at this early stage, most campaigns spend a larger percentage of their receipts on fundraising and staff expenses. (For example, Senate Majority Leader Harry Reid raised $3.3 million and spent $976,000, or about 30 percent.) Shelby has a whopping $14.8 million cash-on-hand as July began.

Trey Grayson, Kentucky's Republican secretary of State, raised $603,000 in this year's second quarter for a potential 2010 Senate campaign, even though Republican incumbent Jim Bunning says he still plans to seek re-election.

According to my analysis of Grayson's report (one of the few to be on file today in the Senate Office of Public Records ahead of tonight's deadline), elected officials were among the donors to his "exploratory" campaign. They included state Reps. Scott Brinkman, Brent Housman and Alecia Webb-Edgington.

Other elected officials who gave to Grayson's effort included K.C. Crosbie, a councilwoman in Lexington, and Hal Heiner, a councilman in Louisville.

A possible bid for the 2010 Republican Senate nomination in Kentucky certainly won't enable eye surgeon Rand Paul to rake in the mega-millions in campaign donations procured by his much better-known father -- Texas Republican Rep. Ron Paul -- when he campaigned for the 2008 Republican presidential nomination on his strongly libertarian-tinged platform.

But the younger Paul, a first-time candidate for public office, has taken a page from his father's playbook by going online to build up the treasury for the "exploratory" Senate campaign committee he established in May. And he pronounces himself pleased with the fact that his receipts topped $100,000 in a little more than a month.

Paul's organization said it hasn't held any fundraising events, instead collecting mostly small contributions "from over 1,200 regular people who nickle and dimed their way to an impressive showing" in advance of the candidate's fundraising report for the year's second quarter, which is due to be filed by July 15.

He didn't exactly refuse to answer but Sen. Mitch McConnell of Kentucky didn't exactly endorse his home-state colleague Jim Bunning in his 2010 race, either.

"Your fellow Republican senator ... Jim Bunning, is mad at you, I think it's fair to say," said "Fox News Sunday" host Chris Wallace to McConnell. "He says you don't want him to seek re-election and that while you've given money to other GOP incumbents, you've stiffed him.

You can put this all to rest right now, Senator," Wallace said. "I'm going to give you the opportunity. Do you endorse Jim Bunning for re-election?"

Kentucky Republican Rand Paul, the son of Texas congressman and 2008 presidential candidate Ron Paul, has organized an "exploratory" campaign for the Senate seat of Republican incumbent Jim Bunning.

Rand Paul, an eye surgeon from Bowling Green, disclosed his plans Thursday night on Rachel Maddow's MSNBC program and in a press release on Friday.

"The Republican Party's lost their mojo," Paul said on MSNBC. He added, "We've lost our believability. It's not that our message is so bad, but we've said we're fiscal conservatives, and then we doubled the deficit."